Well it's more the latter. I'm just experimenting right now. What I want is to modify how the Luke Skywalker model looks. I want it to look like this:
So what I'm doing is borrowing part of the leather jacket from Infinity Blade's DF Kyle Katarn (again this is just experimentation) so that it looks like a vest for Luke.
Now what I'm doing is taking the Luke model from JA, changing the skin, and trying to build a new .pk3 file. Problem is that I can't get the game to recognize it. My experience in skinning is almost non-existant, so I am not sure exactly what the basics are for JA skinning.