I believe you are referring to the WWII zip gun? I have not heard this "plastic gun" that was printed on a 3D printer referred to by any name resembling that which was issued as a throw away piece in WWII. Quite frankly, that was a very cheap and limited use piece. The printed gun for this demo was anything but cheap considering the equipment and time it took. I'd hate to think this gun was designed, built and fired for any reason than to establish that it could be done.
I do not believe that it's purpose was to manufacture a cheap, single shot pistol for mass production or sale. Quite frankly, the thing is not very concealable, is not likely very reliable, and being a single shot .22, would not be a very practical self defense weapon.
If I recall, the “Liberator” was a single shot .45 caliber metal stamping. I think the designer is just making a point by using that name. The same guy has produced the receiver for a AR-15 but said in one of his videos he wanted something totally plastic to prove it could be done.
The only zip gun I know from my much younger days was fabricated from a car antenna. Very inaccurate.