The satellite module is usually on that side or an HD radio iboc
module. Yes get a Most jumper and see if the sound comes back
or you can also route it out of the Most loop at the Most junction
as described in the Logic 7 links.
If you run your cars Vin through one of the Free online Vin checkers
it will tell you what if came with in the way of options.
https://www.bmwvin.com/
The module should be labeled.
As far as I know everything that is in the loop would be in the area
you are looking at.
Be sure to use the original head unit as it is programmed for
L7 and whatever option the module in the trunk covers.