Strange (FACTORY) Holes in Trunk Lid

There use to be a popular anti rust treatment they would apply to cars. Ziebart was the name of the company. They would drill holes like that to spray the ant rust liquid in areas that they couldn't other wise get to. They would plug the holes afterward with those body plug looking plugs. Maybe this was a body panel that was on a car that was treated? They would drill holes in door jambs also and then use those plugs.