I haven't seen the actual kits but each version of the actual a/c is different. IIRC, the RF-4E is an export- only version and was created by putting an C nose onto an E fighter. The E is of course a very different bird than a C, which is really just an Air Force B (with also many differences.) The short answer is you would have to cut the nose off the E, glue it to the B, add a refueling receptacle, rear consoles, thicker tires, wings, etc etc etc.
The very best solution is to build a Marine RF-4B, an Israeli RF-4E, and wait the few months it will take for Hasegawa to release an RF-4C, LOL
HTH,
Gary