When you change models and textures, there is no stat changes besides rate of ire due to the animations I guess. But no, damage and recoil and stuff like that can't be changed by modding.
I'll put your last sentence the way it should be, ok?
Yes, recoil, damage, any other stat, can be modified using mods. But you would have to decode the .txt files in attributes.rez, which is very hard. So at this point of time, no, we can't unless you decode it.