I understand the intent, but feel that there are so many other loopholes that put much worse weapons on the street than a printer. Besides, my prints can barely sustain normal use, much less a bullet being fired from them. I would think that this is more of a risk to the person holding the gun than who it's pointing at.
Someone assassinated the former Japanese PM with a block of wood, two small pieces of pipe, and some simple electronics, and that was extremely advanced for an amateur hand crafted firearm
Spend enough time in the sticks as a teenager and I guarantee a pipe shotgun will basically materialize out of thin air at some point