The Screw(3x30) is the cheapest item from this partsfiche.
twenty-two components are shown in this Rf900r 1998 (w) (e02 E04 E18 E22 E24 E25 E34 E39) / P37 Turnsignal Lamp (model T/v/w) exploded diagram.
In this schematic the "Gasket (nas)" is used most often.