Is this a U.S.G.I. gauge?

Would this be a U.S.G.I. headspace gauge for the M1 Rifle? Probably a dumb question, seeing as how it's stamped, but I have never seen one before. It is stamped :

WALTON GAUGE CO.
ORD DEPT U.S.A.
HEADSPACE GAUGE
CAL.30
C7719C
1.942FCG 18

It measures 2&3/16 in. long and came with package and tag.

Thanks, Greg V

Yes, it is US GI. Ordnance had a gage for every 1000th dimension from 1.940 thru 1.950. It even had a few large ones. I had a 1.956 years ago.