Bongo Fury

I picked up a 96 2.5D Bongo today which the previous owner said had been converted to 2WD from 4WD by the previous owner. Is there anyway from looking underneath that I can tell this is the case and whats needed to change it back. Or alternatively, any way to check it has always been a 2WD and just been given a bit of duff info?

thanks

Check the chassis number, numbers starting SGL3 were 2WD and SGL5 were 4WD

And you can see a front drive shaft and diff on a 4wd.

It would be a huge amount of work to add 4wd to an original 2wd.