Parts such as the Rear Case: Plate,prim Brg Se, Bolt,flange,6x20, B/brg Rad N/com, O-ring,63x3 (arai are included in the Gl1500 Goldwing 1988 (j) Switzerland / Kph Rear Case parts fiche.
In this schematic the "Bolt,flange 8x45" is used most often.
Of all the components used in this assembly the Case Comp,rear is the most expensive.