While DD was making progress with its 3D-printed gun experiment, the company managed to get a license to become a legal manufacturer and vendor of guns, somewhat muddling the legal status of the 3D-printed gun, a weapon anyone with a 3D-printer could make at home.
There's absolutely no "muddling" here. You can do any amount of gunsmithing you want, at home, and it's legal without a manufacturer's license up to a very specific point. You can feel free to make a stock, a trigger, a pistol grip, etc., but just don't make a receiver. On some guns there's a lower and upper receiver, in which case you can make the lower without the license. Make the upper without a license and you're in trouble.
Side note: don't make a silencer either. They are easy enough to make and you don't need the license to make it, but you do need the license to own it.
The Liberator still has some more testing to go through
It's probably damn close to a 1-shot gun and then replace the barrel. It also won't have rifling so it won't be accurate. The cartridge next to the gun in the picture appears to be a .22 short which is probably the maximum the plastic can handle. I wouldn't want to be anywhere near this thing when a .38 or 9mm cartridge is fired. The plastic won't contain the significant force.
but the lack of requiring a license — and the gun’s lack of a serial number — are unsettling thoughts.
Much like you don't technically need a license to make a gun, you don't need a license to drive a car. Simple guns have been made by machinists for a long, long time. And you don't need a serial number on a gun either but if you are found with a gun sans serial number it's a felony with huge prison time. But cops see guns with serial numbers shaved off all the time.
I understand the threat of plastic guns getting on a plane or through security but you'd still need to get a bullet through as well which wouldn't be so easy.