The number on the frame that is revealed when you swing out the cylinder is an assembly number. This number is also on the yoke and most likely the inside of the side plate. The serial number is the number stamped on the butt of the grip frame. This number should also be stamped on the yoke edge facing the cylinder (viewable through the charge holes), the rear face of the cylinder, the front surface of the ejector star, and possibly the bottom of the rear sight tang. Even with the stamping on the barrel and refinish it looks like a nice K Frame target model revolver.