Mystery Ground Strap?

[Slotts]

Have a good look at the second picture the OP shows where the screw hole has three barbs per side. Then zoom in on the ground strap for the map light that is up for grabs on ebay.

1970-74 CHALLENGER CUDA E BODY MOPAR OE DASH MAP LIGHT WIRING HARNESS | eBay

<p dir="ltr" style="margin-top:0; margin-bottom:0;">1970-74 CHALLENGER CUDA E BODY MOPAR OE DASH MAP LIGHT WIRING HARNESS. </p> <p dir="ltr" style="margin-top:0; margin-bottom:0;"> Will only ship to the lower 48 states. Items are sold “AS IS” , with no written or implied warranty. Only Pay Pal...

www.ebay.com

 

[Steve340]

I don't think it is a seat tag or a radio support.
Notice the little raised barbs to bite through paint.
I think it is some kind of earth strap - either for the map light or perhaps the heater box.
The factory may have used the same strap in two places?