The original addon broke after a GMod update making the addon and also the game unusable when installed. So I reported the issue to GiGaBiTe, the past maintainer of this addon. They said they not longer can mantain the addon for time reasons and asked me to reupload it with a fix.

Originally posted by GiGaBiTe:

I unfortunately cannot maintain this addon anymore. I lost the source files to this addon years ago, which would require me to decompile the GMA package to get into it again and make changes.

Currently, I do not have the time to dig into this problem and fix it because of work obligations. You're free to decompile and re-release a fixed version if you'd like. If you do, let me know and I will delist this version so people won't keep downloading a broken addon, else it will stay up so the model files are at least available.

Screenshot: https://i.imgur.com/02b1f44.png