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The #5055xx is the assembly.

ASSEMBLY (factory work) #s: These multi-digit numbers of 3 to 5 digits, are on the yoke at the hinge, in the ‘yoke cut’ on frame opposite the yoke near the hinge, and inside of the sideplate, for the pre war and early post war period. The assembly # in the yoke cut of the frame was relocated to the left side of grip frame after model #s were assigned in 1957 and the serial # was eventually added in the ‘yoke cut’ where the assembly #, now moved to the left side of the grip frame, used to be. You know they are assembly (factory work) #s because of those 3 locations that always match on guns that are original, and that’s the only usefulness for them after guns leave the factory: still used to this day, long after serial number locations decreased.

The serial number 459JXX is from 1971.

The letter is usually left out of the grip # stamp at the factory.

__________________
Jim
S&WCA #819