Something unique in a 1934 Beretta rifling marks???
No, it's just that apparently there's no one left in England available to the movie and TV industry who actually knows anything at all about real guns.
Witness the cable TV shows being done for the History Channel and Military channels about WWI, WWII, Korea, Vietnam, and the Sand Wars.
You'll see WWI and WWII German troops "firing" British Lee Enfield rifles.
Russian Commie revolutionary's firing Lee Enfield rifles in 1917 Moscow.
German troops firing at Hitler during the Beer Hall revolt with Lee Enfield rifles.
American troops wearing British web gear, canteens, and uniform jackets.
101st Airborne paratroopers in Easy Company tossing British Mill bombs instead of American pineapple grenades.
American Paratroopers wearing obvious black work boots instead of paratrooper jump boots.
Hitler shaving his mustache with a WWII British Commando knife.
M1 Rifles, M1 Carbines, and Thompson guns blazing away, but the bolts are not moving.
American troops wearing obviously plastic prop helmets that are WAY too small.
In one scene there's WWI German troops firing rifles from a trench.
Some of them are using Mauser rifles, and some are using obviously prop Lee Enfield rifles WITH THE BOLT HANDLE ON THE WRONG SIDE.
No the film is not reversed, the Mauser's have the bolt on the right side.
The reason for all this foolishness...... Most of these shows are made in England where no one appears to know anything about icky real guns.