Rear Speaker Grill and Location

I have a 69 Eliminator with AM radio and rear speaker option.Trying to clarify that it is one speaker only and the location as well as type of speaker grill.I took the car apart many years ago and have one speaker and grill.It is the 68 style 6x9 spkr and grill .I believe it is original to the car but doesnt line up with any of factory holes in rear deck,so really not sure where it goes.I have an NOS AM radio kit and NOS rear spkr kit that is for Mustang so the spkr and grill are different.Anyone have a car that is original and can verify?
Thanks

Typically if the car has a single rear speaker teamed with an AM radio it is in the center position which will align with a 6" X 9" speaker. It is a rectangular hole but it will align.

Thank you so much.Sounds about what I figured but wasnt sure ,was a long time ago I diassambled.