Parts such as the Rear Combination Lamp (vl800c E28): Bolt(6x16), Cushion, Screw(3x12), Lens are included in the Vl800c Boulevard C50 2011 (l1) Usa Californ Canada (e03 E33 E28) Rear Combination Lamp (vl800c E28) parts fiche.
On this parts fiche the Screw(3x12) is the most specified component.