Quoted from chubtoad13:Ad listing: Classic Stern Backglass locking mechanism and upper trim
Earlier Stern games did not use the same type of set up that the later ones did. The "tabs" to lock the backglass in were on the locking bar which moves via the lock / key, much like the style that Bally used. Check out the pic here - https://www.ipdb.org/showpic.pl?id=2377&picno=53115&zoom=1.
Jim