Nice find. I believe mine is dated 1944. Used by army for invasion. Navy tended to have blue cloth covered version. Airborne had a fancier alrge inflatable wone with CO2 cartridges and hole.
I have one that I bought at an auction for the low price of $2.00. Is marked with a G.& ? letter 1945 and a broad arrow pointing up.Also has a V501 inside a small circle. Still holds air.