[John Sabato]

Under high magnification, I can see that the digit under the second "5" is a "4".

The focus of your photo would need to be macro sharp to compare the two "5"'s to see if they were struck by the same die. It could be as simple as a mistake corrected at the factory, or as complex as a recent attempt at fraud. Knowing the actual owner history for this gun can speak volumes.

For example, if you know that the current owner or seller is the actual veteran who brought it home, the chances that the overstamp is an indication of attempted fraud is very low... but if this gun has passed through several owners, there is no way to know "UNLESS" the forensics of the two "5" numbers show them to have been stamped by the exact same die...

I hope this mini-lesson has been helpful.