The Liberators were provided to French Resistance fighters. "Never been fired, only dropped once"? The Liberators were provided to French Resistance fighters. "Never been fired, only dropped once"?Yupper.
The Sterling however, was built like a tank and served for over 60 years.
Those are M-3 “Grease Gun” submachine guns. Fired a .45ACP cartridge. They had barrels that would allow them to fire 9x19 rounds in some cases.
They were produced to bring down the cost of sub-guns, because the Thompson “tommy gun” was (and still is) a very expensive, exquisitely machined piece of work. Those are mostly sheet metal stampings.