I just received a similar one, I think. Flaming bomb, S No.4 Mk 1* on left receiver wall, with "US PROPERTY" along top left rail, Serial no. 62C8###. Immediately below the serial number (on the wrist) is what appears to be the capital letter "B". I see that some reference show a stamp "B" refers to BSA, and since there is the BNP stamp on top of receiver ring, this one had been to England, I presume. I am not real certain how to distinguish a "B" for BSA from the combined LB for Long Branch.