Well, I don't know much about these gear driven machines, but our 401 has the shaft like the one in your second pic. The bobbin winder drives off of the hand wheel.
Our 500 has the shaft like your top picture and the bobbin winder drives off the little protrusion on top.
So, I'd pretty much agree that the machine with the protrusion on the shaft has a motor from a 500 series or similar machine.
From what I've heard, (this is not gospel) the motors are the same, just the shafts are different.
Joe