Perhaps another reason the later marks aren't modeled as often is the complex landing gear. With the Griffon power plant came a larger prop so the gear legs needed to be lengthened.
Has anyone ever acurately replicated this gear action in a model?
The landing gear legs were also lengthened to provide sufficient ground clearance for the new, larger propeller; a system to compress the legs by 8 inches as they retracted and re-extend them upon lowering was devised to overcome the problems posed by the lack of room in which the longer legs initially had to retract.