I've got several gray stones Nam era knives. Some are clearly separate S's, some not so obvious, at least to me. Anyone got a picture of the earliest stamp with the S incorporated? Joe.
That stamp is on a knife that's kind of unusual. Its a Model 16 double hilt with sawteeth but what's weird it appears to have a Maurice Johnson smooth back with a stone pocket. The sheath appears to be waxed but is only marked "16".