Hey Hoby have to compare the body shapes. Might be possible to widen the pup routes and if can fit 5 tuners on a MMB-4 kit 3+2 that may work. Or are the MMB-5 a 4+1 config ? That would work. As long as a 4 string neck is wide enough for 5 strings. Might have to fit a 5 string neck to it.
Sorry Toshi about the thread jack mate !