On this parts fiche the Collet,retainer is the most specified component.
A sample from the products for the Rocker Arms/valves ('80-'81 Kl25 include: Seat,valve Inner Spr, Screw-pan Head,6x14, Collet,retainer, Valve-intake.
The Seat,valve Inner Spr is the lowest priced item on this Rocker Arms/valves ('80-'81 Kl25 schematic.