I agree with Charlie's comments above, and offer the two following conjectures: (1) The gun is a Defense Supply Co. gun ( Guard Gun) shipped to a civilian destination by S&W. After WW2 the gun was donated by the civilian recepient ( war plant?) to an ROTC or National Guard unit, and was stamped US Property by the armorer, or (2) a Reserve or Guard unit purchased the gun from a war plant after WW2, and then stamped it. I mention the latter event, as I was a member of the Calif. National Guard just after WW2, and was provided funds from my unit's recreational money to buy small arms for recreational hunting and plinking while training in Death Valley locations. These purchases were then stamped "U.S.Property." I bought .22 rifles, pistols and shotguns. We already had all the Victory models we needed, so I didn't buy anymore, however some units might have wanted Victory Models, for what ever reason. Ed #15