I have a 1983 510 that needs a tuner. The existing ones look kind of like 180° Schallers, ie, the screw tab is parallel to the key shaft, but don’t have removable buttons or any markings, but any modern tuner I’ve seen will leave the old screw hole showing. Does anybody know what Bob was using back then? Or better yet where I might find one that would work on the bass side. Any help appreciated.