Sorry I don't have any practical information to offer except that from the 4-5 Ghia owners I've known - the "derigur" in ownership is not just one but having 3 examples, all in various states of disrepair, on hand, preferably parked on your front lawn.
Seriously, maybe parts are hard to come by, but people pick up multiple cars with the intent of cannibalizing 2-3 to end up with a single complete & working copy. Good luck, they are cool looking cars.