The 28 gauge has only "S" on the initial plate. I don't know who WOS could be. I always thought that the "S" was Norman Strebe's initial. Norman was a large gun dealer and gunsmithing entempreneur in nearby District Heights. His logo recoil pad is on the gun and the gun is restocked and refinished, something his shop specialized in. He was an important Parker and Fox collector and I thought this gun may have been his using bird gun. Your mention of the WOS initials on the GH grade Parker makes me think that my theory may be incorrect.