My 15 year old son, the reason we have this P20, wants to hide a modern radio behind the existing Plymouth / Mopar Model 604 Radio face plate / grill. We have the unit out of the car, but I can't see how the faceplate is attached to the radio case. The closest I can figure out is perhaps there is some special very thin wrench that can be used to loosen two nuts around the tuning and volume knobs. Is that how they are separated / connected?