Aidon,
Here is a link to a Williams target bank refurbishment. Start at thread #18. https://pinside.com/pinball/forum/topic/williams-1963-major-league-restoration
There was a spring on the back of the target in the early games. The bank will remove quite easily to work on at your bench. A good cleaning will help usually. The screw heads in your picture appear to be trapping the ball also. The seem to be an obstacle in them selves.