Pushbutton to 4-Speed - Pushbutton Delete Plate?

All the pictures I've pulled up for the dash of a '64 GT have a slide control to the left of the pushbuttons, the function of which I know not. http://valiant50.co.za/joomla/index.php/members-garages/1964-dodge-dart The few delete plates I've seen offered don't have the opening for the slider. What am I missing here?

That's for the parking sprag. When the lever is down, it pulls on a cable to move a finger inside the transmission that locks into a toothed wheel and keeps the output shaft from turning. To put the car in park, you push "N" to put it in neutral, then slide the lever down. You can also just slide it down and it'll engage "N" automatically. When it's time to drive away, you slide the lever up and then press "D".

When you take that cover plate off, you'll see that the pushbutton assembly and lever are all one mechanism. A manual trans doesn't have a parking sprag, so the lever goes away with the pushbuttons.