I didn't even own a Mountain CD when I bought (one of) Felix' EB 1, I knew Mississippi Queen, Nantucket Sleighride and Theme from an Imaginary Western, that was it. I only bought a compilation afterwards because I felt guilty not having anything from them ... The dramatic aspects (shot by wife), if I'm perfectly honest, held more of a morbid fascination for me than Felix' legacy as a bassist.
It's difficult for me to imagine a celebrity owned instrument where the celebrity factor would be of real importance to me, not even a Deep Purple bassist pre-owned one would mean that much to me. I like to know where an instrument is from though, like my Allen Woody which belonged to Dr Bassman or my 86 TBird owned by George C. That has an affectionate interest because I know these people and if only through this forum.
Or basses with a story like my gun hole EB-0L or my Bicentennial "that came came from the cold". It had found its way to East Berlin and was played in an East German blues band until the wall fell. The irony of a bass commemorating the "imperialist" USA being played, red, white and blue eagle and all, in a communist country for decades never fails to fascinate me. There can't have been a lot of Bicentennials in East Germany, let me tell you, you hardly saw them in West Germany. The only German "celebrity" bassist I can think of who played one was the bass player of Kraut proggies Eloy.