What version are you meaning, a turret without a rear ventilator?
As far as the Army was concerned, the only “versions” were tanks of different engine types (first and foremost), armament, and the M4A3E2. The suspension was a detail that wasn’t really important in segregating vehicles until well after the war. You can’t go too deep into details or combinations of parts in discussions of “rarity” because there were a lot of detail changes. That, coupled with the intentional interchangeability of components, produced all sorts of combinations that had no significance beyond indicating the parts available for assembly at the time. For example, M4A1(76) tanks could have three brands of engine booster coils and two brands of air cleaners. Would the a tank with a Delco-Remy coil and a Donaldson air cleaner be a different “version” than a tank with an Eclipse coil and a Vortox air cleaner?
KL