It seems to me that this is an uphill battle seeing how quickly additive metal printing is going. With each year it's getting easier for an amateur to make their own effective firearm from scratch and and a design downloaded from the Internet.
Since (at least in the Glock's case) the polymer frame is the federally defined and controlled 'weapon' and everything else (barrel/slide/trigger-assy/etc) simple accessories that anyone can own, it would seem we're already there. I presume Glock shape files are already out in the wild.