Steve, I may have made a mistake. The #450xxx was hand engraved on the frame. The number #455xxx is stamped. What does Wilson say is the year for #455xxx? Since it's stamped, I'm assuming the 455 is the actual serial number, right?
A few years back I was given an old Detective Special. Based on other posts, I'm guessing it's a first edition but am hoping you can verify it. It has the half-moon sight, unshrouded ejector pin nearly as long as the barrel, patent dates stamped thru Oct 5 1926, serial #450xxx.