thirty-one components are listed in the schematic for this Gs400 1978 (c) (e01 E02 E04 E17 E18 E21 E22 E24 E25 E30 E34 E39) Rear Fender .
The lowest price component in this Rear Fender parts-list fiche is the Washer(6.5x18x1).
Of all the components used in this assembly the Fender,rear is the most expensive.