Parts such as the Left Handle Switch (ds100c: Switch,dimmer, Cotter Pin, Nut,cable Adjuster, Block,lighting/dimmer are included in the Ds100 1981 (x) Usa (e03) Left Handle Switch (ds100c parts fiche.
The most reasonably priced component used on the Ds100 1981 (x) Usa (e03) Left Handle Switch (ds100c is the Lock Washer.