No P-47B's saw combat.
The only appreciable difference between the D-11 we have in game and the Factory C is no WEP and no drop tank. While there were a significant number of C's that saw service in England, there would be little value, IMO, added by including the C, especially seeing how pretty much all of the C's that did see combat in Europe were upgraded in the field to a D standard (i.e. WEP and a centerline drop tank).
If you want to ask for a missing variant, IMO, the most bang for the designer's time would be for the D-23 or M.