Look at the rear face of the cylinder, the flat underside of the barrel, and the underside of the ejector star. At the probable time of this gun's original manufacture, the serial number once found on the butt would be repeated in those locations. There should be a K prefix, as the basic frame of that gun dates from the late 1940s through 1955.
There are some oddities, though. The stocks are from before 1920, the rear sight appears to be of the prewar style that was not used after WWII, and the front sight blade has been either ground down or replaced to work with the non-standard rear sight.
Can you provide a photograph of the top of the rear sight so we can see how many screws there are in it and how large they are?
The number you see on the concealed frame surface that is revealed when you swing the cylinder open is a soft-fitting number. It had no meaning once the gun was given final assembly and sent to inventory.