alt Hacker NewsThe model files and designs are protected speech, yes.... but free speech doesn't really follow the transitive property. Just because you can have a copy of the Anarchists Cookbook doesn't mean that building the things in the book are protected speech.
Not in California but generally 3d printing or otherwise self-manufacturing firearms is legal per the 2nd amendment, and publishing files is protected expressive activity (I bet there are some ITAR cutouts for weapons but I suspect that doesn't come into play here).