Well, woodguru is not really asking for a valuation of the gun or our opinions on the authenticity of the story, he is just asking if there is a way to trace the gun based on the little information he has. '
If he could recall the name of the auction house and the approximate date, he could probably get some information, as those auctions keep meticulous records. Without information on the magazine, the auction house, or even the approximate date, I am afraid the trail is cold.
It would be hard for Germany to lay claim to the gun unless it were taken from a museum or its original owner was Jewish and it was taken first by the Nazi authorities. Generally, those guns were considered legitimate war trophies.
Goering was carrying an S&W when he was captured, but he had hundreds of guns in his collection. He somehow acquired thousands more during the war, as every other pistol brought back by a GI belonged to "ol' Herman, yessir, I tooken it off him myself personal like."