I know that. This particular fox stamp was Curly's, as several others have confirmed. It was the current head of Northstar West, Matt Denison, who theorized these were probably Curly parts on a different stock. Whether they were originally part of an all-Curly gun or sold for a special project nobody knows. The original owner's name of "G. Shriener" is on the barrel.
"Know that the pistol has no value, we practically don't use it. We need grenades, rifles, machine guns, and explosives."
Mordechai Anielewicz, April 23, 1943