1954
@1947
1972
1948
If you call S&W, they will tell you.
Look on the butt of the revolver.
i think 1966
Your Smith and Wesson K-22 was made in the year 1948,with the serial number K20708.That year the serial numbers were K18732-K73121.I hope that you find this informative.
1953
K130218 was produced in 1951
Minty K22's can bring $500, or more in rare variations. I don't think that is the serial number however. The serial number will be found on the butt of the gun, not inside the crane.
You must call S&W. The number you list does not follow normal conventions.