For $20 buy yourself peace of mind by going through an FFL. They will check all that needs to be checked, the gun will into the books that it is no longer yours, and you get a receipt with the serial number as proof of transferring out.
Not arguing the peace of mind bit at all and completely understand the fear of the Feds. That said, Delaware specifically allows the face to face transfer of a firearm between 2 individuals as long as the purchaser possesses a valid CCDW permit. That is the law. That was a fighting point last year and our 2A groups protected that right. It cost money, time and manpower to keep this ability when the attempt to strip it away took place after Newtown.
Technically, if you get a copy of the purchasers CCDW permit, a copy of their Delaware drivers license and a quick bill of sale with their name and serial number the law should protect you. Should LEO's need the info you can provide the bill of sale (your receipt), the CCDW permit copy (showing you followed the law) and their Delaware drivers license to expedite locating the individual. It's your lawful right and to dismiss it dismisses the money, time and manpower it took to retain that right.
Again, I'm not arguing the peace of mind. You have laws that supposedly protect your rights. If you give into fear those laws are useless and as time goes by you will loose more and more rights. Think the 2A groups in Delaware will fight to retain this law next time it comes up? Doubtful.
Just saying...