Paul, you are probably pretty close to what actually happened. These connectors seem to be showing up mostly on the 73's who were playing the final song for the first generation Mustang. Detroit assembly was preparing for the launch of the new 1974 Mustang which shared nothing component wise with the previous Mustang. A lot of parts for the Mustang were probably being depleted at a faster rate than the slower selling Cougar. Since they both shared the same assembly line and chassis it would be easy to substitute what Cougar parts you needed to "Get them out the door". The Ford parts catalog does not list a power seat switch, seat motor, or power seat tracks (which would have the transmissions for seat movements) for any 71-73 Mustang. A DSO option would certainly be possible with the Cougar parts. If that is the case, normally there should be four numbers after the DSO # on your door label. Tracking down that info now can be very hard as David can tell you in trying to find DSO info on his black 73 Vert. I think it would be great to end up with a car that was internally ordered by Ford. There would be no telling what kind of "One of" or special goodies you would find on your car!!