Yup, barrel is printed as well. Entire gun is ABS plastic, which sounds absurd until you realize that it's only a .22 being fired through it, and it's only intended to be used for one shot. This round is so weak that it's explosive charge is comparable to the primer charge on other rounds.
Only two things aren't printed, the firing pin (which is a nail), and an additional hunk of metal that goes in it so it will be detectable with a metal detector (there are other laws against "stealth" weapons that have no metal in them).
I was going to say, I think the last place I read about plastic firearms was in a Robert Ludlum novel (spy-thriller type stuff). Though if the "additional hunk of metal" is optional and included for plausible legality, I can see there being some political blowback regardless.
Yeah, If you have any experience with creating your own 3D CAD files for printing it would be trivial to go into files yourself and fill in the void for the metal. I doubt it would have a significant impact on the gun's performance. While I can't see this particular model being used as as spy weapon, the potential is certainly there as the technology improves.
Only two things aren't printed, the firing pin (which is a nail), and an additional hunk of metal that goes in it so it will be detectable with a metal detector (there are other laws against "stealth" weapons that have no metal in them).