So rare to have been on the large number of GMC pickups produced during these 10 years! Most GMC truck enthusiasts have never seen one or even have any idea what they look like if they see one not labeled at a swap meet.
This heavy metal one piece stamped bracket is secured to the left rear stake pocket and holds the same 4 “ round light used all 10 years.
This photo is of the “real thing’. It is correct for the left side as pickups did not come with right side taillights.