I love this place! sometimes the info you are looking for just shows up right in front of you! Let me explain. Recently A friend asked me to go up to Tennessee to clean out the family home as it had sat vacant for the last ten years. When I left he gave me a piece of paper with a combination on it, he said if I found a safe this was the combo. Well I did and found some very interesting items, one was a S&W model 10-5 that was probably brand new when it was placed in the safe another was a Colt 25 auto and a Walther model 4 that his grandfather had brought back from WWII. This model 4 appears to be identical to yours but without the "M" stamp. It is however missing the grips I would like to find a pair of grips to make it complete and give it back to him all cleaned up. Sorry for the long post but the story goes with the gun. The serial # is 224167 any idea of how old it is?