I don't know if USFA still works on them, but the generally accepted "guru" of Lightnings is Eldon Penner in Nevada. I was referred to him by Long Hunter. I have a USFA Lightning and had Eldon tune it up. Works wonderfully, and is now my main match rifle.
Eldon can also still build you a new AWA Lightning from parts - he was their gunsmith.
You can contact him at hepenner@aol.com