I stumbled onto this older thread and figured I'd update it. I had the gun lettered and it did ship to the NYPD on 10/11/46. RM Vivas was kind enough to research the gun and the shield number on the back was correct. Don't know why the style is different but the Equipment Section records show the gun was sold to the officer with that shield number.
Vivas included newspaper articles written about the officer who had that gun. He used this gun in a shootout with 4 gunmen in 1950 and was awarded the Medal for Valor. He was even assigned to my old precinct. This $350 old .38 has become my most valuable firearm. Very glad I snapped it up. I couldn't find any more info on the officer, other than he died in 1991 in Florida. The latest he could have stayed on the job was 1982, and it is a rare bird who stays until they force him out, I wonder how this gun found its way to a gun shop in NE PA? I doubt he took the gun with him to Florida and it found it's way back to the NE. I guess he could have given it to a child who stayed here and eventually sold it, but the obituary doesn't mention a wife or children.