w/o a registration database, nobody will know if you sell a gun to your buddy, brother-in-law, father, hunting buddy....whoever. It's completely unenforceable.
now on the other hand, a disgruntled neighbor could say he saw you buy a gun in your driveway from somebody and you would have to prove it otherwise. (I have to go dig around and look for some receipts)
Unless you bought it at an FFL after the effective date
The chair is against the wall has a long mustache.