I believe that at one time there might have been a metal pin that had a flared base that was mounted at that spot.
The pin should be exposed to the ball hits, and not the rubber ring.
It acts like a baffle for the ball so that it could go into the eject hole.
Andromeda had a pin at the upper left lane in order to baffle the ball into the eject hole.
I'm assuming that it is the same setup.