Because of the refinish, the gun is probably not worth more than $300. To detract more from the value aspect, the original front sight was completely removed and some sort of non standard sight replaced it. The stocks are Jay Scott faux pearl. Colt owned the grip replacement Jay Scott company at one time. They made aftermarket grips for various guns, also including S&W models. The original missing grips would have been checkered black walnut with brass liners for the screw and eschutcheon nut inlets. The 32 cal and 38 cal Colt Police Positives were not continued by Colt in the post WWII era. Also, the barrel has been cut down. Standard length barrels were 4,5 and 6 inches. Shorter barrels could be custom ordered.
In unadulterated and original condition, having a Railway Express stamping on the gun would have increased the value a small amount. It makes no differende now with all the replacements and modifications on this particular gun. Just check to make sure it's safe to shoot and has no mechanical issues, and go out and enjoy it.
Your Police Positive SN 364347 was manufactured in 1934.
Mike
Member of S&W Forum and Colt Forum since 2005