I've seen a 1974 4001 for sale in Brisbane Aus that has enclosed style Grover tuners. I had a Rick mid seventies and was sure the tuners were the open Schaller style. Most photos I have seen of 4001 models seem to have these as well but some look to have the Grovers. Anyone know if Rickenbacker used both for a while or switched over at some point? Maybe the Grovers were a modification by the owner?