Merging models

Ok, I am planning to make a mod for the source engine however to make it not feel really cheap I want to create
custom hand models for the weapons. Modelling isn’t something I’m good at so I was wondering can someone
please merge the Garrysmod weapons and Counter-Strike Source hand models to one file to replace the half-life 2
models or tell me how I might be able to?

so, if i’ve read that right.

you want half life 2 weapons but with the counterstrike hands.

Yea, pretty much.