EUP Model Skins

Hi, was trying to re-texture my EUP model files for the firefighters, but realised there were only 3 model/texture files. Is it possible to add an extra file for my fourth texture, or will EUP not read it?

I also tried to swap the model files with another unused model which has 4 variations, however, it wasn’t sensing the texture of the boots, and my models spawned without shoes in FiveM.

Any help would be gladly appreciated!