Some items from this specific schematic: Bolt, Screw, O-ring (d:3.5 Id:54.4), Lock Washer.
With a quantity of three pieces, the Lock Washer is the most used part in the MUFFLER (DS185T) diagram.
The most reasonably priced component used on the Ds185 1979 (n) Usa (e03) Muffler (ds185t) is the Bolt 10x9.