You can do it in two ways:
* Use
Crowbar and decompile the model and change the path of the view model in the generated qc file, and then compile it again
* Rename all "model files" to something new, and
use a hex editor to change the path inside the mdl file
Just to remember, original csgo view models don't have built in arm models, it is however possible to fix this in the qc file (when decompiled). Don't have the code for doing it as I am writing this though
If you have garrysmod, you can download a lot of models from
here