If I'm not mistaken his production #'s are wrong. "75 S code 4 speeds in the GT/CS" -there were 111 produced as a S code 4 speed and 75 "X" code automatics. Plus, as has already been stated you could order an "S" Code without the GT package, one of my cruising buddies has a 1968 fastback "S" code 390 auto without the GT package ( has the c stripe but, no fog lights and no heavy duty suspension and drum brakes).
Don