"plastic" sealed beams

[Dragsinger]

At one point, cars that were equipped the two rectangular sealed beams per side [example 4651 or 4656 style beams] [also my 1982 3rd gen Camaro]

So far, I am not finding that replacement plastic bulb, only a glass replacement.

Looking for help or part numbers or good condition used plastic. I need four bulbs, does not matter high or low beam, they are for appearance only.