Hello Simmer down
If the gun we are talking about is the one on the left in your first picture, someone has filed the serial number off the butt. If they restamped it on the side of the grip frame (which is what I think you are saying) they probably just accidentally left out one digit. As I mentioned in my earlier post, that is the only explanation that makes any sense, given what we know.
I don't know for sure, but with the original serial number filed off and an incorrect one stamped on the frame, this gun may very well be illegal to own. This is not a good situation.
JP

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Jack
SWCA #2475, SWHF #318