Rino, if you really don't know the truck's history, I'd pull the 7 bolts and replace the bypass hose along with the thermostat. The whole mess really swings out of the way and it will remind you of the good old days with the unencumbered small block Darts.
You can replace the thermostat without pulling the aluminum piece, but that thermostat is way down in a hole, and there isn't a chance to check the condition of the bypass hose.

The bypass hose on my 93 was original to the truck, and rock hard, it came off in pieces. I was happy I pulled the aluminum piece off and checked it. Gene