Cleon
Legend
Sure. You sound like you're more of a Howard Purist than I am.
Then again, this sounds like me, after all. I pick and choose to serve the atmosphere of my game.
I contain multitudes. My Conan literary criticism self is a Howard purist, while my Conan in RPGs self tends more towards' "whatever tickles my fancy".
When they have a disagreement it's settled with Broadswords At Dawn.

I think they are. A mail shirt would be AC 5 (or AC +5, for AC 15, in 3.5) in D&D, while it's light armor in Conan. A breast plate is medium armor in Conan where in D&D, I think that's considered plate or half-plate, a heavy armor.
That might be a result of d20 D&D's two different kinds of chain armour getting mixed up.
A chain shirt is light armour with a +4 armour bonus, while chainmail is medium armour with a +5 armour bonus.
Even then, all warriors get the Heavy Armor Feat. And, I don't think heavy armor would be that available, even if a few warriors in the clan did pick up a piece or two off their enemies.
True, but that's the best I could come up with without changing the rule and allowing the Barbarian class to be familiar with Light and Medium armors only.
That's curious, the d20 SRD version of the Barbarian class isn't skilled in heavy armour. Did they change that for Conan?
A Hunting Arrow in the Conan RPG does 1d8 damage, but your point is still true: Minimum armor of a Leather Jerkin is DR 4. Heck, leather bracers and a small helm is DR 2.
That seems rather too much for leather. Then again, I have read that the Conan RPG tends to have heavily armored characters be more-or-less immune to light weapons. I remember seeing a "actual play" thread where the DM was saying the party's nobleman could basically ignore a small horde of Picts because their hunting bows and hatchets didn't do enough damage to threaten his armour.
That's probably realistic but I'm not sure how Conanistic it is. The big guy seemed to shear through chainmail like rotten string - but then, he was supposedly one of the strongest men alive.