(Note: Ilbranteloth had a similar objection.)
This is more storytelling not indicated by the OP's description. This scenario basically re-writes the scene. The more effort you infer the DM went through to justify not giving the ranger a simple perception roll, the more implausible it is that he cannot remember a whit of it when writing in his own defense.
Also, this doesn't match what we do know. The blacksmith studies the armor, and comes up with an offer. The ranger doesn't like it, then makes his appraisal. THEN the blacksmith notices the ring. They are quite far into the scene at this point.
Question: Do either of you really believe this scenario happened? Follow on for Yardiff, which of these now four scenarios you've spoken in favor of do you believe really happened?
To begin with, do you really think that the sentences in the quote below are all that happened at the table, verbatim, and no other things were said?
At the blacksmith (a half-orc they already know from before) he presents the bundled up armor. The blacksmith studies it, making note that the armor is very damaged (from the battles) and it would lower the price. At the mention of the price being lowered, the ranger asks if he can make a int check to learn how much such an armor would go for, he rolls well. The half-orc notices the magical ring and immediately asks "Are you looking to sell the whole thing?" to which the ranger immediately says yes. The blacksmith offers a price, the ranger isn't too sure since it was lower than expected. The blacksmith argues that with the damage would lower the price and he still needed to make a profit. The ranger still seems to have a hard time agreeing. The blacksmith quickly adds that it's money up-front. The ranger agrees.
So if we're going with this as the verbatim account, here's what I see:
While there is some debate as to whether the ranger saw the ring/gauntlets and knew they were important, I maintain that was not the case. The rest of the party was doing something, and "meanwhile" the barbarian was examining, and then bundling up the armor. Even if the ranger did see it, he obviously didn't put any importance on it which is supported by later statements.
Regardless, if I was the DM, and the party examined it, bundled it, never mentioned it again, nor attempted to identify, examine or state they had later separated the gauntlets and ring from the bundle, it is still bundled.
--
So, the ranger apparently doesn't think he is dealing with anything more than an adamantine suit of armor. If he does think it is, it's up to him to mention it. At our table, anybody else could have reminded him (or me). It appears that's the case at his table, but nobody did. The fact that he sold another suit of armor that they specifically told him not to is a pretty good indication that the players have some communication/attention issues to address.
It's still all bundled together by rope, some of it's readily visible, some is not. The armor is visibly damaged (very). -
Established before the interaction
He places the armor on the counter and says, "How much can I get for this?"
No description in OP, I haven't added any
The blacksmith studies it, turning over the bundle several times. He's seen plate armor before, and his initial look confirms that it is very damaged. Since it's going to take time to unbundle it, he notes that the damage will lower the price. No point in opening it all up if the ranger isn't going to accept a reasonable price. He doesn't give a value yet, just says, "hey, this looks pretty beat up so I can't give you top gold."
OP says he studied it. I don't even think he would have needed to pick it up (see below), but it certainly doesn't say he unties the bundle and lays the pieces out on the counter. So I haven't added it. Note that he does NOT come up with an offer. He just says that whatever offer he gives will be lower than full price because it's damaged.
Upon hearing this, the ranger asks (outside of the game), "do I have any idea of how much such an armor would sell for?" He rolls, the DM says yes, you have a good idea.
No indication that he appraises the armor, just asks if he knows how much it would sell for. I might have asked if he was going to take the armor back, examine and appraise it, or if he just wanted a general idea. He didn't so I didn't change anything.
Since this implies the ranger then told the smith, "Yes, I know the price will be lower, but take a look and let me know how much anyway," the smith starts to examine more closely and unbundle the armor, notices the ring and stops, attempting to keep it out of the ranger's view. (There could have been a sleight of hand check here).
Although he doesn't indicate that the smith unbundles the armor, or even examines it, he does say that he notices the ring immediately. My assumption, since there is no description of how we got from "do I know what a suit of armor is worth" to "the smith immediately notices the ring" I assume that he starts to examine/unbundle it and can now see what he couldn't see before. Otherwise he would have asked the question earlier. Since the DM doesn't mention the ring to the ranger, I would also assume that it is not within his field of vision at the time. This is very plausible to me (see below and earlier posts). I would have at least had a sleight of hand or deception check against a passive perception here. He didn't, I don't think I'm adding anything other than the least amount of action to connect the two points.
"Are you looking to sell the whole thing?"
"Yes."
This following conversation is implied, we don't know the exact conversation as the DM didn't report it (A deception check could have been made here). I'm not adding anything that wasn't described.:
"700 gp"
"That seems low"
"It's pretty damaged, I'll need to put in a lot of work before I can sell it."
"I don't know, can you go any higher?"
"No, but it's money up front. I'll pay you right now."
"Well, OK"
--
None of what I'm describing alters the fiction, or is illogical or implausible with the 9 sentence description given. Basically, my interpretation adds less to the fiction than the smith unbundles all of the armor, and lays them out neatly on the table. When working in retail, and we were knowledgeable about our merchandise, we would move things around enough to make sure that everything was there. That's it. We would avoid unpackaging things as much as possible, just more work. When purchasing a used item, it would vary, depending on the item. Like I noted about the stack of Magic cards, unless the seller was indicating there was something of value, I'd just do a quick check to make sure they were actually Magic cards, a general sense of the condition, and quantity. If it was a damaged suit of armor, that I would have to repair, I'd look for key things - the decoration (takes more work), are all the parts there? (just need to see a part of each piece, no need to see them completely), and the material. He's not trying to sell anything that requires a true "appraisal."
Why? Well, first, since it's damaged it will need to be repaired. So the actual value of the armor is of less value. Another example is used guitars. My buddy builds and repairs guitars. Occasionally I'll spot something that might interest him. It's good to know if the original parts are there. Otherwise it's mostly a question of the year (we're usually only talking about Gibson Les Pauls). So a 10-second glance is usually all I need to identify if it's something he's interested in. He's typically not interested in paying any more than 50% of what he can sell it for. So we start at that price. If the seller isn't interested, no point in spending any more time discussing it. That's also a negotiation tactic. We set our price, and if they say no, we say, "Great then, good luck." A lot of times the guy will sort of stand around, thing about it, then come back up and say, "well, OK, I think I can do that" and we buy it. Other times they'll say, "no it's worth more than that, here's why."
That's when it's worth spending a little more time. If the ranger says "Well, OK, but this suit was worn by so-and-so, and it's made with Sanherian Adamantine, and has a ring attached to the gauntlets, so I think this particular suit is worth more." Then it warrants a closer examination. Otherwise the smith probably doesn't have to spend much effort on it at all.
I once tried to get a loan with my guitar. It's a Gibson Les Paul, all original hardware, original silverburst finish. The finish has worn off the neck from playing, and I've seen numerous examples from a couple of years where this was a fairly common problem. He asked if it was the original finish. I said yes. In this case I knew more about the guitar and the issues with the finish then he did, but no matter what I told him, he was convinced it was refinished and only offered a price based on that. I also deal with model trains, and run into the same thing very, very frequently. People bring something that's 50 years old and think it's worth a bunch. Right off the bat I tell them it's probably worthless. Today's modelers expect more accurate models, with much better fidelity. Unless it's in perfect condition, and you can find a collector looking for that particular piece, it will sell for a couple of bucks.
So no, I don't think the smith would have taken all of the pieces out, unless the ranger objected with some reason that would require him to look at all the pieces individually.
Do I think everybody else would feel this way? Probably not. I have my own unique experiences on which to base my opinion. They are also the same ones that help me build the world my players play in. Am I more descriptive? Well more than the OP. I don't know how descriptive the DM was in the actual game, I wasn't there.
Later posts indicate that at least half of the party had no problem with it, the ranger was upset for making a mistake, but apparently doesn't seem to fault the DM or how he handled it, and the final player either doesn't like it or wasn't around for further comment. This also supports my general perspective on the events in that the players at that table aren't objecting that he didn't remind him, didn't give him enough information, or didn't make enough skill checks.
Can I parse it a different way and come to a different conclusion? Of course. This just happens to be the first conclusion I came to, in seconds, without even thinking about it. It's the one that makes the most sense to me, without any further thought about it. The responses on where I've elaborated are simply to explain the many things that pop into my head that support that conclusion. Many of those thoughts occur simply because of past life experiences. None of which are unique to me, although the particular mix of experiences is. Another experience thrown into the mix is 35+ years of DMing. That doesn't make me better, or right, it just means there are a lot of past experiences buried in my subconscious that mysteriously coalesce to form an opinion when reading a post like this.
As we've continued the discussion, not only does it still make the most sense to me, but I don't feel like my reasoning has been illogical, unreasonable, or strained. The cool thing is, there are times on this board and others where my reasoning has fallen apart and I've changed my mind. Maybe it doesn't happen all that often, but it does happen. Regardless of however much experience I have, I can always learn new things.
Ilbranteloth