I have a census of 5 different Guild F612 serial numbers, all of which I almost bought at a point since I took an interest in Guild guitars. So you add John Denver's (2)-F612's, then the one that TX owns, another F612 that is owned by yet another LTG member, and you can account for 9 of which I know of. So far I have owned one of these 9 F612's.
I was disappointed that the only luthiers that showed an enthusuastic interest in helping me restore this F612 were at the Martin factory. The folks in Nazareth, PA answered all my questions pertaining to restoring it, but stated that it is their policy to only restore Martin guitars.
I sold that F612 and resolved to play only guitars that are current, and for which I have located luthiers that can do some good quality work necessary to maintain them.