I call them "Interior rear side panels". And, just so eveyone knows this: The very early cars did not have removable rear seat latch covers. Sometime in December or January Fomoco added the removable covers so the latch could be adjusted without taking the car apart. You need to know which ones you need, early or late.
It would take time but maybe you can trade your "speakered" panels to someone who is about to get the saw out on theirs to install some speakers.