Neil,
The Shelby scoops have smooth edges at the leading edge of the scoop opening and the GT/CS scoops have a witness line. The Shelbys are functional and the GT/CS are not. I cannot comment on the shape because I have never held them side by side.
I believe the witness line is visible if you carfully look at some of the photos in the gallery of scoops. I won't be at the house this evening so won't be able to sent you a photo.
Rgds
Bill