With a quantity of twelve pieces, the Bolt 6x30 is the most used part in the FILTER - OIL PUMP diagram.
Parts such as the Filter - Oil Pump: Screw 6x12, Pin(4x15.8), Washer, Spring are included in the Gs450s 1988 (j) (e04 E22 E34 E77) Filter - Oil Pump parts fiche.
The lowest price component in this Filter - Oil Pump parts-list fiche is the Stud 6x20.