Actually i just sold my Sig 2022 9mm to a local guy days ago. What i did here in Vegas (regardless to a friend or stranger) was:
Make a "Bill of Sale" for each buyer and the seller. Stating the model #, serial #, caliber, make and date. Full name, address, DOB and phone # of both parties. Get the seller to write down his name and sign.
Show each other's Driver License, CCW and surrender the gun's blue card to the buyer.
Buyer gives money and seller says thank you
You can if u want, take pictures of ewch other's Driver License and CCW. Which i did too.