My experience has been that the earlier ones (with the upside-down question-mark-shaped B-flat-tuba-style connector - between the 4th rotor and tuning slide) tend to barely play up to A=440, and the later ones (with the same part shortened to a sharp right angle) tend to require that the tuning slide be pulled way out - to achieve A=440.
I owned a couple of those (both with the sharp-right-angle piece), both to which I added my own style of 5th rotor.
One of them ended up eventually being owned by Ron Bishop, and was sold by his estate to someone else.
I believe the other one (??) ended up at a Memphis high school. I've been over there since I've seen it, and did not see it there. I have no idea whether that one "walked off" or what.
The "Bishop" one featured a choice of GG semitone or GG whole tone (piggyback horizontal system).
The first piece I played (after adding the 5th valve) was in the pit - playing the opera, "The Love for Three Oranges" (quite a few LOW pitches written throughout).