Rear Housing

So I have what is probably a stupid question. Have a 69 Dart with a 8 and 3/4 rear end. Was driving today and heard a noise, stopped and found a couple of pieces of metal on the road. On further inspection they used to be as the pic showed but on passenger side. Previous owner said they were to rotate housing to be better in line with transmission. What are they called and are they needed. Thank's