The Stovebolt Site Forums The Shop Area General Truck Talk hole below radio speaker on right?

I have a 53 Chevy 3600 and have always wondered what the stamped hole is below and to the right of the radio speaker. The Factory Assembly manual seems to indicate that it was the throttle cable hole for RD trucks. Does it have some sort of cover/plug in LD trucks or was that where the cigarette lighter option went?

TIA