Of all the components used in this assembly the Tail Lamp Unit Assy is the most expensive.
Some items from this specific schematic: Screw Pan Head, Cord, Tail Lamp, Washer(6a1), Bulb, Tail Lamp (12v 32/3cp).
The most reasonably priced component used on the At2 1972 Usa Taillight is the Washer(6a1).