You mean rear window louvers?
By any chance, is your hair starting to grow a little longer in the back and shorter up front?
Window louvers looked great on the second and third generation cars, yet there is a reason you don't oft see them on first gens:
(1). Because they weren't even popular in the late 60's except on racecars
(2). They don't look good on a first gen
I've thought about it a few times, but honestly I couldn't imagine how they'd look on the new Camaro. First gen Camaros never wore window louvers so I don't have a reference as to how they'd look on our 5th gens.