it was said to be a 5' barrel, yes. it also had this 31x21 stamped over some other numbers ( pic ), so maybe something is up? I knew nothing about these guns till I saw this one and checked it out before layaway. I figured $450 was a good price so i grabbed it. I just noticed... both sides of the barrel have a different marking, the ampersand, is a different style on either side. WTH? is that normal?
Yes, those other numbers are normal. You'll find various other numbers/letters/markings, on the frame under the grips. They are assembly/fitter marks to keep track of things during the manufacturing/finishing process.
You did ok... that 5" barrel is not that common, and many people including myself, consider them special enough to pay a premium for. I think a 5" barrel N-Frame is a prefect match, I only have 2 of them... if someone offered to exchange 5" barreled versions of the N-Frames I have in my safe... I would have it open so fast it would make your head spin.
That looks to be a good solid shooter with mostly cosmetic issues not really worth the expense to refinish the gun.
But you need to address the rusting, it doesn't look to be anything beyond surface rust. For guns I've bought like that, I take the grips off and drown it in WD-40 (Kroil is good too), then let it marinate for at least a few hours to soften it up (sometimes I let it set overnight).
Then I use the edge of a real copper penny (made before 1963) and use it to "work" the softened rust off with it, like a scrapper. The soft copper will wear and leave smear marks, but those clean right off with a bore cleaner like Hoppes #9.
What you'll end up with is a decent looking surface, wipe off all of the WD-40 and then oil with a good rust preventive oil.
Now go shoot it... and enjoy.