I bought a GM factory rear spoiler for my 79' C3 and decided not to use it. Does anyone know what year C3's this spoiler will fit? All C3' or just certain years? Not sure how I could find this information thru GM.

Just couldn't bring myself to drill mounting holes in my 79.

Hello, Any year with a rubber bumper I would guess. The early ones had it moulded in. Unless you have one that is mounted above the body. 

If it's the duck tail lip spoiler that started on the '78 pace car then I suspect it would fit anything from '74 to '79. 

74 Had that split rear rubber bumper.  75 to 79 all had the same one piece rear bumper so that is most likely the years it would fit on.

Mine is a bolt on spoiler. Not molded into rear bumper. Thanks

That's the one that came on the '78 Pace Car. It should fit all the aforementioned years except perhaps the '74 since it had the split rear bumper.