There were not alot of changes to the 2.5 during it's production .
There are a couple of different versions of main bearings , to do with the location of the locating tabs
Thottle body injection till 91 when they went with multi point injection
There are a few variations to water pumps , depending on whether it was V belt or serpentine belt , the rotation is oposite on those , there are differences to the length of waterpumps too.
A few other subtle variations but they pretty much interchange over a wide range of years with minimal fuss.
I'm gonna sell my 88 Comanche this year , it's a 2.5 / 5spd / 4.10's / short bed 31's (mtr) on rubicon moab rims if you or anyone else is looking for parts or a whole truck