Re: what year did Gibson start doing PAFs for neck and bridge
Gibson started to make p'ups specific to bridge and neck roughly mid/late '70s. The 490R/498T set and the 496R/500T set came 'round then. Then they were Dirty Fingers, the 490R/490T set, then the '57 Classics, then the Burstbuckers.
I know I've forgotten a p'up or two, but I think I'm in the ballpark.
HTH,