OK, thanks so much for your info. Yes, there is an "S" preceding the serial number, and the dates you are providing make sense to. He began his job on the police force in 1951. I did not know that this was the only gun he ever carried, but now I suspect it was. I know he was still carrying it 32 years later when he retired. I remember the story that he had money deducted by the city from his paycheck until he finally paid the gun off.