Hurricanes

I’ve started to get interested in doing two or three large scale Hurricanes, and recently Revell has stated they are doing a new tooled one (Hurrricane IIb). I plan on buying three or four in various units. Most will be RAF, but do want to do at least one from the 4th Fighter Group. There is one glitch! They flew Hurricane IIa’s. Can you convert a later mark back to a IIa? If so, what needs to be done?
gary