BOSE confusion

The car allegedly comes with BOSE speakers, but has a (broken) Pioneer satnav head unit. I would imagine the BOSE system is some kind of proprietary thing, with a hidden amp and maybe integration with a specific head unit? Am I way off target?
What's the easiest way to tell if this system is/was fitted?
Sorry for my lack of knowledge, and any links to the nitty-gritty of these cars are most welcome.


