so I'm the OP and still confused. Trying to figure out if the rear was original to the car - or a possibility. With the 3.91 included in the A31 package is it safe to assume it was a SG. Whatever is in there now is in a 741 case and not a SG. What is the most likely case for a spring special A31 3.91 gear ?

68 Satellite Wagon and a few other ones