"anyone anywhere can use a schematic code to create a gun using a 3D printer"

False, it would still be illegal for a prohibited person to 3d print a gun, they could download the schematics but making a gun is making a gun whether you use black pipe and a hacksaw or a 3d printer. Anyone could already make a gun at home before 3d printed guns, if you are allowed to own a gun it is already legal to make one.