I don't see an issue here. No new laws, no new regulations on guns. Just check that you are legally entitled to own a gun.
You could log into some online DB with your ID/PW and run the name of the gun buyer. Should be quick and easy. Get a print out or .pdf file that they can buy as many guns as they chose to buy.
Fear is the path to the Dark Side. Fear leads to anger, anger leads to hate, hate leads to suffering.