B.Dudly,
I think I know what John Can is curious about and it might be helpful if you examine the right side of the butt stock to see if it shows signs of any markings or where a plate may have been attached(4 filled screw holes).The modern S&S will not be able to help you, but Jim Cate can.BTW I think I forgot to mention, the reason Sauer had to buy mauser actions from Oberndorf is because Mauser's patents were still in force.
Mike