My girlfriend's grandfather showed me a little jewel while I was visiting. He has the original box, instructions, cleaning brush, and extra recoil spring. Right side grip is cracked, but the blueing is beautiful, looks like 90% conservatively? It was taken off a captured German officer in WWII, and brought home by his father, a member of the 29th division as a souvenir. He is curious about it's value, can anybody help?