[Graham Boak]

I don't think so. Generally, each design needs a dedicated prop. There'd be no difference between making a blade for a 4-blade hub than for a 3-blade hub design. The hub design for a four-blader is perhaps a little tighter but doesn't require more exotic technology, and had already been done for aircraft such as the Do 217M, He 177 or later Ar.240s.

The suggestion that 3-blade props were retained for the benefit of fuselage-mounted armament makes sense to me. Which would perhaps explain why the twin-engine designs went to 4 blades first. The Russians retained 3-blade props too, presumably for the same reason. Also, they were mainly interested in low-level performance. For their more powerful fighters the Japanese went to 4-blade props and wing-mounted armament.