From the maker of jerry's guitars since '72:
I configured the guitar with a plate system for mounting pickups. This allowed for a variety of pickup choices. It was originally set up with three Fender Stratocaster pickups. I also provided Jerry with a second pickup plate for Humbuckers (hum-canceling dual-coil pickups). The 70's were a time of evolution in guitar pickup design, so when Jerry got a new guitar, there was usually a period of experimentation. Then, from time to time Jerry would try new pickups, but once he found what he liked, he usually stuck with it. Sometimes Jerry felt that an old set of pickups. would get "tired", so I'd change them out for new ones.