IIRC, unpatched FOT raider recruits were actually raiders (1.27 classifies them as human) and some of them had raider armor which could be donned by humans.
It is possible that one of the merchant encounters has raider armor, but I don't think so.
As a last resort, you can use the entity/level editors to stick some in there for ya.
Except for making you look like a raider, its crap armor though. IIRC raider armor mark II is evquivalent to somewhere between leather armor and leather armor mark II, and regular raider armor is slightly weaker than regular leather.