This schematic depicts all components used in the Cx500 1981 (b) England Rear Cover partslist.
A sample from the products for the Rear Cover include: Gasket,rr.cover, Guide,neutralcord, Oring,27.5mm, Bolt,flange,6x32.
The most reasonably priced component used on the Cx500 1981 (b) England Rear Cover is the Nut Hex 4mm.