charger dash frame question

[Ranidart70]

what went next to the radio on a 68 charger ....I am guessing some kind of option but no idea what it could have been.

Also does anyone know the measurements to drill out the hole for the 4 speed light on the bottom?

 

[Xp29h]

I've got a 69 charger, my dash has same spot. Possibly a spot for a rear speaker pull switch or fader type control. Found a pic online. Not of my car. I found a couple pics like this..