To the OP,
The only thing additional I would suggest (for the future, as you've already shipped) is that you verify the validity of the FFL before shipping. You want to know that (A) they ARE legitimately an FFL, and just as importantly... (B) that their license is CURRENT.
Go to Google and search "ATF FFL check" and you will find an ATF site which allows you to enter only the first 5 and last 5 digits of their license number (some are squirrelly about giving out their full number). The site then verifies their GOOD TIL date on their current license, the business name, and address.
This way there's no way you can be culpible for shipping a gun to a non-FFL who simply CLAIMS they are.
Just a little bit of CYA. What ever happens with the gun after you ship it is none of your concern. And if the FFL balks at giving you their first and last 5 digits, tell the buyer they need to find a different FFL to receive.
In this way YOU can never be on the hook for something bad happening downstream with what you THOUGHT was a gun you legally sold.
Nudge
