studs go through the dash frame, through the heater controls and then the nut.
I hate this set up as it might have been easy at the factory but it sucks thereafter. I cut the studs and plastic posts off and bolt the controls to the dash with a flat head screw and nut. the 70 Dart bezel has two screws through the top edge anyway, plus the nuts for the radio controls. That way you can remove the bezel without any issues and without disturbing the heater controls. Once the bezel is off the heater controls are a lot easier to remove using the flat head screws while you hold the nut in place with your fingers.
