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Under U.S. Laws at the time of WWII, there could be no specific production of weapons for sale to foreign armies. However, any Military weapon that was adopted by the U.S. Military then declared "surplus" by the particular branch (Army, Navy, Air Force.) could be sold. This is why many Number 4 Lee Enfield rifles were stamped "U.S. Government" and adopted as substitute standard by the U.S. Army. BUT, the Army did not have a lot of Ammunition for these rifles, so they declared them "Surplus" and sold them to England. However, the U.S. Navy had millions of rounds of .303 ammunition, but only a few old Lewis guns to use it in, so they declared the .303 Ammunition as "surplus" and sold that ammunition to the British.
On the Prairies, there are several airports that are right on the Border, across from each other, with a large wide "road" between them. Military aircraft could not be flown across the Border, but if parked near the border, and a rope attached to them, could and was hauled across the border on the ground, by Canadian tractors or horses.
The revolver you have is probably an early production model.