I'll reply to my own message as I figured it out and perhaps this may help someone out there in the same predicament.

There are 3 little rubber bumper type gaskets that hold the hold unit onto its metal brace. They look like mini engine mounts. These rubber gaskets are sandwiched between some round metal mini-plates. Those plates have a T-20 torx head screw on top (you'll have to look hard through probably some apparent rust). You'll need to go after the top two plates first, and then go after the third plate last. That last plate is buried underneath the whole set-up. And, to get that third plate, you need to move - not take off - the metal brace that is holding the whole unit to the frame. There are three bolts on that. Take the one that is directly accessible off first, and then just loosen the others and from there, you'll be able to move the metal unit out and slightly off the car rail frame. From here, you can now get after that third mini-plate with a racket.