Parts such as the Seat: Nut, Lock Set,seat, Cushion, Cushion,seat Lock(10x22x6) are included in the Gsx1300bk Bking 2008 (k8) Usa (e03) Seat parts fiche.
The Seat is made up of components including this Seat Assy which is the most expensive.
The lowest price component in this Seat parts-list fiche is the Nut.