I imagined that the FSMs for dealerships were set-up like encyclopedias. Grabbed the volume you needed and went to work. So, I'm curious as to what info was left out for the FSMs the public can buy. Specifically, my '67 FSM is missing chapters/volumes (not sure which label is correct) #s 4, 10, 12, 13, 15, 18, 20. Can anybody shed some light on this?