The Stud 6x20 is the lowest priced item on this Oil Filter - Oil Pump schematic.
The twenty-five Gs450l 1982 (z) (e02 E21 E24 E25 E34 E39) Oil Filter - Oil Pump component parts are all listed in this schematic.
Parts such as the Oil Filter - Oil Pump: Regulator Assembly,engine, Nut, O Ring(d:1.9,id:13), Strainer,engine Oil are included in the Gs450l 1982 (z) (e02 E21 E24 E25 E34 E39) Oil Filter - Oil Pump parts fiche.