Did the water level get up to the carb? Kind of sounds like that rig was in pretty deep. I would jump to conclusion the rest of the driveline must be compromised. Have you put a wrench on to spin the engine, or just hoping to spin it by starter?
FWIW all Mistu 4 cylinder starters from the 70's up to 1996 interchange. When the engine swapped to the right side on the FWDs is a different starter as well as some of the little engines. There may be some exceptions to this that I am not aware of.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.