Midway 4.5" Shuffleboard Trackball (Used)

Original Midway 4.5" track ball that we believe was used on its Shuffleboard and Bowling Alley arcade games from 1978.  This one is not complete, it is missing a optic board and related mounting bracket.  We are not sure if there is something that goes on top (the ball falls out when turned over).  Item is dirty and has been sitting for many years, but should be restorable.

See pictures for more details on its condition.