This joke of a law isn't going to stop any 3D printed handguns from getting made, it will only add one more relatively easy step.
Then what, ban stepper motors?
Don't give them ideas.
But seriously, given that the 3D printer movement started out with people building their own printers from scratch and there continues to be a healthy open-source hardware ecosystem within the community, I can't see this stopping anyone.
Unless you also make it illegal for 3D printers to print 3D printer parts...
You've come a long way, RepRap.