It may well be possible, however may I ask why would someone spend $750 (according to paneristi.com forum) on a gen Fiddy caseback when the Swiss movement that comes in 127 rep is not even near the look, finish and appearance of a gen !? :?
On second thought, I believe you actually have to own a gen Fiddy with real serial no. and certificate of ownership, to be able to request a spare part from OP.
babola