Replacing original radio and dash speaker in 68 Barracuda

I recently bought a RetroSound Redondo and 4x10 stereo speaker replacement for my 1968 Barracuda. I'm just getting started, removed the 90s Pioneer that was hanging under the vent assembly, then removed the vent assembly and a bracket at the rear of the original radio. I can't see anything else that's holding the radio on from underneath - is it necessary to remove the dash bezel to get the radio out? Also is the only way to replace the 4x10 speaker (at the cowl) from underneath? Looks like it's going to be tight to get at.

Any info and/or photos greatly appreciated.
Just a warning, I just returned a Redondo because I couldn't get it to fit a '68 Rallye dash bezel or dash frame. The thumb wheels wouldn't go through the bezel. And as much adjustment as it had, it wasn't enough. Just FYI