Howdy
A little more info....
I was in a hurry when I emailed you the other day. The hole in the end of your slide should be about .720. At around serial number I6000 they changed the hole size to .705. Barrel diameter went from .714 to .696. These are all "in the White" measurements and some could be different from fitting/wear ect...
To the best of my knowledge the cut/weld frames were stopped at around 3660 and the cut/weld slides at shortly there after.
I would have to agree that the gun should probably be retired or fitted with a new top. If you do this then the numbers won't match. If the gun was mine I would keep it in the safe and get a new one as a shooter when they come out. Good guns are easy to find Family history is not.
Let me know if you need any parts.
L8r
Conley
USMC 87-93