It may have some extra value to just the right collector. On the other hand, guns with serial number glitches/corrections that originate at the factory are often ignored by other collectors and dismissed as not being collectible.
For instance, this last weekend I went to an auction and picked up a nice Colt Huntsman 22 semi-auto pistol. Always wanted one and there it was. Got it at a good price, too. When I got home and checked the serial number, low and behold, I discovered that it was a rare "Double S" Huntsman. In 1976, when the gun was made, Colt ran 1336 of these Huntsmans before discovering they had duplicated some serial numbers from the 1950s, so they went back and hand stamped an S before the serial number that already had an S at the end, thus the Double S label. On mine, the extra S was obviously done at the factory, so I know it is the real deal.
Now, I'm sure that somewhere out there there is a Colt fanatic that would pay extra for this gun, but I'm not about to go looking for them. I'm just going to keep the gun and enjoy it for the great little pistol it is. The serial number thing makes it more interesting and adds a bit of charm for me.
