Parts such as the Turn Signal Lamp (e18): Screw, Relay, Turn Signal, Lens, Lens are included in the Gp125 1978 (c) (e01 E02 E04 E06 E13 E17 E18 E21 E22 E24 E30) Turn Signal Lamp (e18) parts fiche.
Of all the components used in this assembly the Lamp, Rear Turn Signal is the most expensive.