Regardless of any numbers, check the headspace before shooting. The 'IAC Alex VA' indicates a Century Arms assembled out of parts bins with zero QC rifle.
"...stamped over..." Put on when the rifle was rebuilt by some other country some time before Century got hold of it. Brits or Greeks, et al. Century's monkies just took a bolt out of the bin, slapped a bolt head on and shoved it in without bother to check to see if the headspace was ok.
Rumoured to be a total of 7,589 made in 1941. The receiver is from 1941, but the rest of it likely is not.