On King of Diamonds, there is 1 bulb centered between both lanterns, (masked off by either the wooden insert or piece of cardboard, don't remember), and is supposed to have a 455 flasher. On Sing Along, the "Music" Sign on the backglass calls for 2 flashers that lite during game-over. During this period, Gtb. seemed to have several games with 1 or 2 flashers in the head, some tied in with game-over, and some not.

I remember Gtb. Baseball is another example where the entire game title is illuminated only at game over.

Other than the 2 "Music" and the "Last Ball in Play" Flashers on Sing Along, all other lighting is general illumination.