The large rectangle in the center is a cover over the griddle. It too has a "Thermal Eye" thermostatic control so you can set the griddle temperature.

If it is like mine, grease can drain into a catch cup with a weighted switch that will light up an reminder when it is time to empty the cup. I imagine all the indicator lights on this one are in the frosted section between the two outlets. One of the outlets is tied to the oven/burner timer with the button in the center, the other outlet is always live. I assume all the controls and wiring are the same over a range of years, with just the handles and fascia getting a periodic refresh.

Here is the manual for mine. Be amazed at all the features and enjoy the zany artwork of the time! It was my grandmother's pride. When it came to be time to divide up the estate the only thing I called dibs on was the stove.