I believe the books are:
Monster Manual 3
Monster Vault
Monster Vault: Threats to Nentir Vale
Dark Sun Creature Catalog
Neverwinter Campaign Setting
The Book of Vile Darkness
The Shadowfell
Madness at Gardmore Abbey
HS1 and HS2
Halls of Undermountain
Marauders of the Dune Sea
Tomb of Horrors
Dragon #396 and up?
Dungeon #177 and up?
There's no exact clear dividing line since there isn't really a mechanical difference between 'MM3 grade' and prior art monsters.
I would put it this way: Demonomicon was pretty much the book which came out right before MM3. I think some of the monsters in Demonomicon could easily be considered on par with MM3 designs, and other ones not so much. Its even less clear with stuff which appeared in Dragon, which may have had a long lead time. Some stuff produced by people who were aware of the general updates to monsters could have appeared earlier than MM3 and embody the same concepts. Just as easily there's stuff which appeared quite a bit later which clearly does not.
Beyond that, a lot of even early monster design is quite solid. MM1 orcs for instance are pretty solid monsters, kobolds too. Probably more than not the lower level monsters are pretty good (hobgoblins, meh, Spectres BLAH!). I don't think every monster is great simply because it is in MV or MM3 either!
Anyway, if you think a monster falls below the damage output guidelines for later monsters, just tweak the damage expressions, that helps a lot with a great number of monsters.
The best giveaway, in theory, is the statblock format. The new style statblocks are pretty much guaranteed to be modernized monsters and usually the quality is better. Definitely the format itself is a bit nicer.
Once the new statblock was introduced, I had a hard time even looking through older monsters. I suppose what I really need to do is keep a copy of the MM3 on an index card handy for on-the-fly-conversion mathematically.
But, again, as you note, it's more than just the math. IME, most of the MM3+ foes are better designed to lead to more dynamic fights, while it's hit-or-miss on the earlier ones, some of which, admittedly, are pretty great.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.