First off, I'm not a lawyer nor do I know anything about GA laws. I winter in AZ and we have pretty liberal gun laws out there as you know. I asked the same question of a FFL dealer in regards to a private sale to an individual - what was required. Basically, it can be done there (from my understanding) by just a face to face sale. I asked how a person would know if he was selling to a felon or not and he stated that if that was a personal concern, go to an FFL license holder, transfer to them and in turn, it could then be transferred to the new buyer. That way there would be a paper trail on it. Of course the FFL holder would charge a nominal fee for this service.
Personally, if I was doing it, and I wanted the "personal peace of mind", I would do the B of S and also request a photostat of the purchaser's drivers license which would give his name, address and photo and I'd attach it to the B of S and file it away. That way, if there was ever a question or problem, you would be able to supply that information and a photo. Yea, yea . . . I know about privacy. Myself though, I would have no problem with doing that if I was making a private purchase like that. If I was the seller and the prospective buyer didn't want to allow that, then there would be no sale.
I know every state has their own restrictions that have to be abided by. Myself, I would have a hard time living with myself if I made a private sale to an individual that there could possibly be a question as to their background and I found out later that the weapon was used in crime or a hiomicide.
In the case of the OP, could this transaction not be completed by utilizing a FFL license holder to transfer the pistol through so there could never be a question about either the seller or the purchaser?