8 tracks were available with any radio. There was 4 different 8 track units used (in 69 anyway), the was two 2 knob units that mounted under the dash, and two 4 knob units that mounted forward facing on the console. If you had a console, you got the console mounted version, otherwise it was mounted below the glove box on the passenger side of the dash. The AM (RPO U63) and AM/FM mono radios (RPO U69) used the dash mounted speaker only unless they were ordered with RPO U80 "Auxilliary Speaker" and then they had a second speaker in the rear pacakage tray and a dash mounted fader knob. The 8 tracks used 4 speakers (2 front, 2 rear) which they shared with the AM/FM stereo radios (RPO U79). The mono radios shared the right rear speaker with the 8 track (ie RPO U80 was included with RPOU57 when combined with RPO U63 or RPOU69) but otherwise the two systems are completely separate.
If you looking to buy an original setup, be prepared to cough up about 1000 bucks. And don't buy a console mounted one without the armrest pad, as they aren't repro'ed and are very hard to find.