I have one of those radios,and it even works--but not in stereo any more,one side doesn't have any audio output...but it does work on AM,FM,and CB...probably needs one output transistor,I hear its not a real difficult thing to fix..
This one is all self contained,I had another one from a'77 Caddy that looked exactly the same,but used a separate "box" under the dash for the CB part of it..
I have no idea what they are worth now,but when I took both to a swap meet a few times,only one person wanted the CB "box" only--I was reluctant to sell it separate,but he didn't want it--so I got the 15 bucks I was asking for it all,and I left the radio part in the free pile,seeing it was of no use without the CB "box"..
I kept the other one in case I decided to use it in my van or some other GM truck,but its still in storage...