The nuances of AM speaker brackets ('65 Barracuda)

I have two '65 A bodies (Formula S and Signet convertible) that had factory AM radios. The question I have is: what orientation should be used when attaching the factory speaker bracket to the speaker?

The rotten speaker in the foto, came from the Signet. I could not feel any screws or bolts attaching it to the dashpad, so I decided to remove the heater control for better access. When I removed the heater control, the speaker came crashing down to the floor all by itself. Evidently, it was not attached.

The rebuilt speaker in the foto was in the Formula S. It was in the same shape as the rotten speaker in the foto. I don't know what orientation was used on the bracket for the rebuilt speaker (before the rebuild), because I did not take notes/fotos.

Looking at both speakers together, I see the speaker bracket is attached differently on the two. The rebuilt speaker has the flat portion facing up, the other speaker has the flat portion facing down and some old gasket/silicone can be seen on the topside (this side up seems to have a step/indentation--not flat).

Was the bracket on the speaker that fell out on top of me (the old one) installed correctly or is the bracket on the rebuilt speaker installed correctly? Details, details, details ...

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