Oh well, so it works with vanilla, I can settle with that. The brass doesn't look too bad anyways.

It would just be givng the players that have another GP25 model the default one back, and for people that are already using the default one it would give them the skin, but also give them needless model files.

So if I toss in the default model along this mod, would it override the launcher from the pack and show a sexy black?

The GP25 is using a different model from that AK pack you're using, if you remove the mod or just the GP25 models from the mod's files than you should be able to see your texture edit.