Very nice find. They were around in VN also, and I would not be suprised to find one hiding in a corner of some ARNG arms room somewhere today. Those old military shotguns just seem to hang around forever, probably because they never got shot too much like an M1 or an AR would every year for quals. Not all of the later serial numbers were outfitted as "trench guns" with the bayonet lug/handguard, but were issued as "guard guns" to prisoner details, MPs on post, or as defense weapons for fixed emplacements. I saw those same guns at the US embassy in Saigon, among others.