Stacked together, these would make 2, 3 or 5 gears of each type. So my guess is that these gears will help 973 add 1-2 window motors to their shoulder joint that assists with anti-backdrive of their arm. Yet I dunno how that would affect their PID when doing 'over the shoulder' scoring (pick up from the front, rotate the arm and score at the back).
Their render from earlier this year:
http://www.chiefdelphi.com/media/photos/36953
At first I thought the middle gear would be used for a dog gear coupling where the dog gear only has 2 possible coupling positions (180 degrees from each other), yet that setup would shear the bolts/rivets holding the plate gears together. It's an interesting design for a solid steel gear though.