Well, I learned something new today then. Interesting info on earlier chokes.
One idea that might interest you regarding the chokes. Could someone make essentially an adapter so you wouldn't have to cut or re-thread the barrel. This would save any inherent collector value, but would give you what you are after.
It would look like a barrel segment and would have to be custom cut to fit your current/existing threads at one end. Then, extend the barrel by the length needed in order to have the thickness to then use a different type of screw-in choke. In other words, one end would screw in like a proper factory choke to your existing threads. Then, there'd be a small tube that would look like an extended choke but it would have internal threads at the other end to convert it to your desired choke pattern.
I have a SPAS-12 which has external threads and I am having something made that will convert those external threads from those obsolete chokes, to the internal Benelli Mobil chokes. I realize those are going out of favor too, but I have around a dozen Benelli's that all use them. Only my pair of M4's use the newer chokes.