If I had to make a gun-to-my-head kind of guess, based on the date of manufacture (1939), maybe foreign sales to UK, which was already at war and ahead of us in restricting precious metals (hence the ALLOY) and plating (hence the gun blue finish). Way too early for Lend-Lease, and even a little too early for Cash-and-Carry. Or some other customer with coincidentally similar requirements. Very intriguing. Especially the ALLOY STEEL marking. That's generally associated with "New Emergency" triple alloys, but they weren't invented until late 1941 and early 1942. It's too bad someone lopped off the 1-1/4" jaws end and made it a SOE, but still, a very cool wrench.