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.
From what I understand, given IANAL and don't own one:
Background checks: Yes
Waiting period: no
Crimes: any felony, or domestic violence charges
Gun shows: AFAIK that's never actually been true
Other: Probably 16 or 18+ but I don't think there is anything federal
Explosives: lots of paper, similar to an automatic firearm