Thanks guys! I had no idea the third speaker was installed in that location. I run my firebird top down 98% of the time too haha! I'm running the original am radio with just the original center dash speaker. It's ok, but hard to hear at higher speeds, so I was thinking of adding a rear speaker(s). Nothing high tech, just want more sound coming from the rear. I like it original, so I'd like to avoid cutting holes. Any suggestions?

Any truth about the speakers originally being mounted in the back of the rear seat pointing towards the front of the car? If yes, you would think that the sound would be muffled by the seat itself, but a little more sound is better than just the original dash speaker right?