

That is perfectly consistent with the serial number. That indicates your revolver was produced after about June of 1922. There is stamped "Made in USA" on right side forward and above the trigger and trigger guard. What I can tell you is that stocks from the 1920s had no medallion at all.

We can hold off on deciding this until I can see pictures. But let's not try to figure it out with words. I'm not quite sure what you are describing here. A screw head and checkering around that and the silver SW logo as mentioned before. There is a single diamond shape that is flat and recessed. If it is absent, the gun was made between about 1920 and mid-year 1922. But one thing you should look for is the words "Made in USA" on the right side of the frame, just below the cylinder. If there is no diamond, then the stocks come from the post-1968 period. Is there a smooth diamond shape around the screw holes? The checkering would surround that.

The stocks themselves sound like postwar Magna stocks. Your description of the grips is a bit confusing, but I think what you are describing is a grip adapter, where you see the Pachmayr name. It would have a very different action (internally) than the postwar M&P that became the Model 10. The Model 10 was not produced until 1958.
GRIPS FOR SMITH AND WESSON MODEL 10 SERIAL NUMBER
That serial number points to the early 1920s. The other three are the rear face of the yoke, the underside of the extractor star and the inside of the right grip panel (it will only be on the original stocks, which you don't seem to have). The serial number locations you mentioned are three of the original six places where S&W put the serial number in the period during which your revolver was produced.
