There are only two races in KOTOR, Human and Droid. Wookiees and Zabrak are a Human sub-race. So the User limitation property only tells the game whether it is for Droids or Humans. In K1, Wookiees are restricted from using robes and such via baseitems.2da. I thought that the Sub-race property added in TSL could be used to do the same directly in the UTI, but it seems selecting Human as the sub-race just acts the same as the User Limitation. You can limit and item only to Bao-Dur or Wookiees, but not restrict them. That would still have to be done in baseitems.2da. @JCarter426 might have to weigh in on that. I have vague memories of discussing the denysubrace column in the past, whether or not it can be tallied to cover more than one sub-race.
Armour and robes are divided into body types for different armour classes. What model is assigned for each is defined in appearance.2da. Revan's robes uses its own unique body type, body J. Hence the model name is PxBJ. You'll want to read up on how that all works before going further.