Correct. In industrial motors than can be had either way but, they cant be switched to make it one way or another. Rear geartrains can be found in flat nose vehicles or stub nose vehicles like buses and deliverey trucks and construction equipment. They are that because of space limitations and ease of maintance and accesability for the mechanics.
But I just did some research and all 12v are front geartrain motors. 24v's are when they started that.

 

If I were to buy one of these where would I find a engine tranny adaptor for a 47rh

 

you should just be able to pull the back plate off a 94-98 cummins 12v out of a dodge truck it should bolt right up

 

K thats what I thought but the problem is trying to find that back plate

 

THe back plate should not be too hard to find being that the cummins are so popular and there are plenty of them sitting in junk yards