CS:S weapons

Ok so I want to add some custom weapons to my gmod, they are not the original css, things like spoon and that, how would I go about making it so that my SWEP lua file reads it, because when I use it it grabs the main one, and the problem is, I’m using about 5 different versions of that one weapon

v_knife_t.mdl is a file that I have 5 times because of the different models, I’ve tried renaming, tried a hex coder, I have no idea how to get garrys mod to grab the model, and the lua IS setup properly. D=