I wouldn't do it unless I had reason to suspect the gun might be stolen. I'd rather not have the State (and the federal government) have a permanent record of my guns' serial number. As far as I know, NCIS checks are kept for a long time, even if the gun is not reported as stolen. It's like running a credit check through Equifax... Equifax makes a note of who pulled your credit score, on what date, and why.
If I DID have reason to think the gun was stolen, and I had this information at the time I bought it, I could be guilty of Theft by Receiving Stolen Property (O.C.G.A. 16-8-7). Unless, of course, I bought it with the intention of helping get it back to its rightful owner.
One time I seriously considered buying a pistol from a crazy homeless guy in midtown Atlanta who approached me, out of the blue, with that proposition. He said that it was a stolen gun that some cop had left in his car unattended. Had I thought that I could complete the transaction safely, and if I had the cash on me (I didn't), I would have done this and then immediately called the cops and reported what this guy told me. I would have given up $20 of my own money, and taken the risk of being arrested (not properly or legally arrested, but it still could happen...) just to get a very dangerous gun out of a bad guy's hands.
Yes, I was armed at the time this crazy homeless guy approached me. No, I didn't even think of drawing on him. I was in "Condition Yellow" at first, then "Condition Orange" as he mentioned the gun and opened his coat to show it to me (I didn't get a good look at it... it could have been an Air Soft or a toy gun...), but then went back to condition Yellow as he made it clear that he was only interested in selling it, not using it himself.
By the way, if he had tried to draw the weapon without me asking him to, I would have felt compelled to stop him, because I'm not going to let a crazy homeless guy brandish a gun on the sidewalk. But it stayed under his coat as we talked.
No, I did not even consider doing a "citizen's arrest." I suppose I could have, since he admitted the commission of at least one felony to me, and I had probable cause to believe him, but what if he lied and he was not actually committing a felony? What if the gun was a perfectly legal toy or replica? What if it was his gun, legally owned? What if.... too many variables for me to mess with. I didn't buy his gun, but I did call the cops ASAP. They never sent an officer out to meet me. They just took a little report over the phone and said they'd keep an eye out for him.
Every so often someone has something that interests me. After setting a price, I call a freind and run the number before I buy. Something to remember. When checking # make sure they enter the caliber as well as the numbers. Different guns can have the same # and you get grabbed for a stolen gun.