67-69 Cuda notchback

I have been around Mopars for over 40 years but i honestly never saw or knew this. At the track yesterday the guy pitted next to me had a beautiful 68 Cuda notchback , ran good too 9.40s, says he bought it in L.A. and put in his own Indy headed big block. I noticed that the top of the roof above the rear window looked different, like the top of the roof line came out then came back in to the top of the window almost mini spoiler looking. He told me that all notch backs look like that. I didnt think so, his car was heavily modified maybe he built it that way. i kept looking at it all day and really couldn't ever remember seeing one. Today I googled 67-69 Cuda notchback and the ones I saw didn't have a roof line like his. My friend and I had a discussion about it today he sent me a picture of another Cuda with the same roofline. Maybe one year only application? Ok A body/ Early Cuda experts school me on this