And to confirm the above logic I just checked the Audio Aux Link circuit diagram for a non-ML equipped MX TV. The outputs are on pins 3 and 5.
This also explains how this sort of setup works (from ML handbook):
… because the TV can receive the Audio from the BeoCenter, and vice versa, but the BL1611 ‘chooses’ whether the TV or BC audio is being sent over Masterlink, according to the source selected elsewhere in the ML network.