Got my hardin 10" today

I put it together, but it is raining. The mount has needle bearings. On the bottom board they have a round steel plate for the bearings to ride on, but the top board has no steel plate.So the bearings just ride on the bare board. As a result, there are little divots in the board from the needle bearings, and you can feel them as the mount swivels. Evidently it is designed this way, as the diagram shows only one steel plate, and the instructions mention only one steel plate. Why doesn't it have two steel plates? It makes no sense to me.