If you had the factory phone, the speakers were installed on either side of the dash and did provide the audio for the phone. They are referenced in a install bulletin and the wires are in the rear fender, you are probably correct for euro versions.
There are eleven speakers out of a seven channel amp, two each in front doors, one each rear door, two pair (2 ohm) in parrallel rear package shelf (bass), one tweeter behind the rearview mirror. I contemplated hooking up the phone speakers, but after the "bose" amp went south, $600 I am not fooling with anything.