Very nice car! The pictures of the Paxton pieces on this car are newer items available today. They are not vintage pieces from the late 1960's.
As far as the option only being available to a Shelby or GT/CS in 1968 is unknown to me. This option was available via "Ford Muscle Parts" over the counter at any Ford dealer in the late 1960's. To my limited knowledge this option was not available directly from Ford, but maybe from Shelby in the 1965 to 1967 years?
Still a great upgrade and a huge performance adder for those who like to go fast!!
Rob