It's amazine what you can find in the books in your own library. I was rummaging through Small Arms of the World, looking for something else, when I found a photo of a S&W Model 39. The serial number was clearly visible on the right side and it was X 143. There was no other inscription on the right side of the frame. It was clearly a very early pistol; short tang and short safety. Does anyone know what this pistol represents in the great scheme of Model 39s and how many more there may have been like it?