In this schematic the "Nut" is used most often.
A sample from the products for the Corner Lamp Cover (gv1400gcg/gch) include: Cover,corner Lamp,left, Spacer, Washer (5.5x14x1.2), Cushion.
The most reasonably priced component used on the Gv1400gc Cavalcade 1986 (g) Usa (e03) Corner Lamp Cover (gv1400gcg/gch) is the Screw.