Help with some fiberglass parts identification?

[Twin Turbo Skylark]

I bought these fiberglass panels for cheap but I am not sure what company made them and not for sure but think they are for a 73-87 Chevy truck.

Have you guys ever seen anything like these before?

I would like to fix up a 73-87 truck one of these days and if these are in fact for this application it might have been a good score...

So anyone know what the heck I have here and who made them?

Thanks in advance and sorry if this is posted in the wrong spot.