Phone buttons on the steering wheel don't mean much: I have them too but they don't work "legitimately" as I have no Bluetooth/hands free indeed. I believe "enhanced Bluetooth preparation" must mean you have the basic Bluetooth as well, but to make sure consult a
BMW official site and/or a
VIN decoder.
Thus you seem correct with your suspicion about the retrofitted head unit you have: it does not look
listed as "officially applicable", so to say (adjust car selection if needed).
