First off welcome!!!

The pics are poor, and my eyes are just as poorer, so I cannot tell if the serial number was reblued. It is possible that is a factory correction for a mislabeling.

If you have a paper trail from the seller, I would not worry about it.

The gun looks to be in nice shape with light use from what I can see, and contrary to stated opinion, if it is in the condition it looks to be in, 650.00 is fine. Keep in mind the target grips are 85-100 dollars. I will take a dozen in that condition with those grips for 450.00

If you have a very clear unaltered butt frame stamped serial number, I would not be worried in the least. Now for the rest of us, what did you get? What is the serial number? A partial of the prefix ( S or N )plus the first 3 numbers would help us date it for you, if you want.

My suggestion, is shoot and enjoy your new gun!!