my grandfather had a 123(?) in the late 50's and early 60's as well as a friend of his. I remember the 2 machines combining oats together one summer when is was young. I am somewhat sure they were 123s but the 2 machines I just mentioned had an unloading auger like a 715. Was machine a different model than a 123, or was the auger an option over gravity unloader. I also remember his grain tank sitting lower behind the operator. I always liked to ride with him even if it was really dirty.