Right…. Had a good look over some old FCOMs from a few different places - and the inside of a bottle of red
If your aircraft has NOT had the software upgrade 34-1368 you will see:
ADIRS furnishes the wind direction and speed. The digital direction and the analog direction (green arrow) reflect both the true north reference.
If it has had the software upgrade 34-1368 (but no hardware pushbuttons fitted) you will see:
ADIRS furnishes the wind direction and speed. The digital direction and the analog direction (green arrow) indicate the north reference in use.
If you have had the upgrade and the hardware pushbuttons fitted and the Polar Nav Function activated, you will see:
ADIRS furnishes the wind direction and speed. The digital direction is with respect to true north, and the analog direction (green arrow) is with respect to magnetic north [...unless TRUE is selected when it references true!].