I was very fortunate to catch the harmonica which Johnny Cash played a few years ago in the West of England where I live. He always threw the harmonica into the audience at the end of the number, at his concerts. I still have it (of course!) and it hasn't been blown since. It is a 'M Hohner' with a letter B written on it in marker pen, which I think was for quick reference. Bflat is etched into the metal, as is 'Marine Band'.
Ted Jones