I'd be surprised if the damage decals exactly matched the amount and position of where the shot struck. I don't know about the actual files etc. but it seems unlikely that the 3D models would be that flexible from my experience.
Are you sure there aren't just a set number of decals in appropriate positions for every model and it simply picks the nearest one to display? Would be a much simpler way of doing it and solve a lot of graphics problems from a dev's perspective.
Course I could be wrong and some poor programmer spent weeks getting this to work when they could have... I dunno
fixed something important
