R11 and rear speaker

On an E-Body, what option got you the rear speaker/fader switch for the Radio.

R 31...my 71 Challenger has this code on the broadcast sheet along with R 11. But since we are on this subject, this option had one speaker in the rear, or two? Package shelf is empty now...

If it’s one speaker, what part number is stamped on the speaker? How were they mounted? Pics anyone?

Single rear speaker on driver's side.

I just took these out of an October '69 built '70 'cuda with factory R22 & R31 (a single speaker with R11 would be the same speaker on the LH side)
both were mounted with 3 screws - - don't know if that's how it left the factory or if one fell out of each speaker

1970 cars with STEREO (AM/FM or AM w/8-track) had two rear speakers VS. one speaker for the mono AM radio - they used the same R31 code for rear speaker(s)

Thanks! I didn’t know they used screws!

Similar to the '69 B-body method of mounting the single rear speaker:

https://board.moparts.org/ubbthread...9/rear-speaker-mounting.html#Post2854909

Good info! Thanks for sharing👍

Thank you for the reply. Very exhaustive. But what about the package tray cardboard? If single speaker, grille were on both sides I guess. Never seen a sigle grille cardboard...

Correct.
Package tray would have driver and passenger side cutouts even with one rear speaker.