M2 carbine serial number and date of manufacture

[CrossedCannons]

Amongst the first 1500 numerical serial numbers the letter A was sometimes added after the numbers and in at least one instance the letter P was observed instead of the A. Of the 28 carbines recorded between 001 and 1500, 22 have the A, 1 has the P, and 5 have no letter after the numbers. The meaning of this A is not known but of the 22 that have the A, 18 of these are known to have been sold to a law enforcement agency. This practice was discontinued after s/n 1500.

You might write Jim Mock and ask him. While he likely may not be able to provide you the date you seek, I am sure he would appreciate a correction to the above, taken from his website.