83/85 240D What is Part # for insert underneath lug nut?

Between the lug nut and the aluminum wheel on an 83 to 85 240D/300D there is a well-shaped insert. The lug nut presses against the insert to hold the tire on. Most of the time you barely notice this insert because its pressed in and never pops out. Unfortunately three of mine did when I bought new tires and now I cant find them. I cant drive the car now.
Does anyone know the Part Number for this item and how I might order it?

Thank you