K-38 Masterpiece, serial number K45924 almost certainly left the factory in 1948. It is a tapered barrel, narrow rib, five-screw variant. A nice piece!
The number on the barrel flat is the serial number, and it will match the one on the butt, the rear face of the cylinder and on the rear edge of the yoke. The number in the yoke cut on the frame has nothing to do with the serial number. It is a parts-tracking number used during assembly.
The stocks on your revolver are much newer than the gun. Those were produced no earlier than 1978.