Dana 20 identification

Ok so I finaly got round to removing the badly adapted dana 20 transfer off the merc diesel, my question now is what parts are the original dana 20 units and which are not. My main concern is the main drive gear and the adapter piece, have they butchered this factory piece or some how joined two pieces together, the other one is the steel plate is that actually normally attached to the dana 20 or is that an add on

 

From the pictures the transfer case input gear is an original piece. The transfer case is a CJ unit '72-'79 judging by the shift linkage. The rest is something it appears someone has made, definitely not original Jeep issue.

 

Looks like to me someone tried to make a divorced transfer case.