2004 bmw x5 3.0 - strange panel dangling from the back right

[hexnuts66]

after further inspection, the part is a plastic square, with two adhesive looking strips hanging by a thick black wire. on this hard plastic plate are two serial numbers:

84 11 1 470 326

BMW 941 742-003

the top number traces back to the cell phone housing in the center console.. the bottom number I couldn't locate anywhere. Is it possible this panel is just a structure to hold the end of the antennae for the phone? does anyone know what i'm talkin about?

it is just dangling below the right muffler and i'm not even sure where it is supposed to be reattached. thanks!