I was trying to do that myself (and failed) before I found out you already made a mod which replaces it all. Thanks alot

Jackets and pants don't. They use the same textures, just different models. The BDU shirt does, though, because, as with all clothing of the same type, it's simply a texture overlayed on top of your character. Spongie's Open Jackets swaps out different textures depending on the state of your item - one for rolled sleeves, one for an open shirt, and one for rolled sleeves AND an open shirt at the same time.

I think I never noticed this. Do the M81 camo patterns turn to vanilla patterns if I use the spongie's jacket open/close/sleeve options?

Legend, thank you.

Yes. I'll look into it.

Could you make a SMUI version of this as well?