Importing models from other games

I’m trying to get models from other source games into Portal 2 (using GCFscape). I’ve gotten it to work before, by simply copying ALL the data from Portal into Portal 2s’ folders, allowing me to view and use Portal 1s’ assets successfully. However, I’ve since cleaned all that away by reinstalling Portal 2, and now I want to be more methodical and import models one at a time. However, they don’t seem to work correctly when I do this. Below is all the files I transferred for the Portal 1 weighted storage cube:

And this is how it looks in hammer:

The models I add all seem to be missing wire frame data, and thus don’t appear at all, either in game or in editor. I’m also not 100% sure what the material path for the models should be (as I’m trying to sort them in custom folders for convenience). What data am I missing and where can I find it? Portal 2 is more then capable of rendering Portal 1 models, but I just seem to have left something out…

P.S. If this is in the wrong forum, please move it. I had trouble figuring out where it belonged.