Adding Speakers to the Duster Package Tray...

We have two cars with the speaker cutouts and the torsion bar lifts, so I know the speakers will fit in there.
I even removed some old 6x9's from the 72 Dart when I made the new tray.
Both cars had the factory cutouts in the metal under the tray.
Okay, so mine did NOT have factory speakers back there, does that mean there are different torsion bars in the ones that came with factory speakers?