But we need a decompiler/compiler (please point me to one if there is!)
The process is this.
1. Decompile CS gun model
2. Decompile hl2 model
3. Import hl2 hand model on the CS hand bones, assign the vertexes and etc.
4. Compile it and you have your CS gun with hl2 hands.
At least that's how i would have done it with the hl1 engine. I'm assuming it's the same method except we have no decompiler yet.