Yer, but that is at the reel end of the belt at the lower seat level.
However, you could be right and the sound at being transmitted and amplified
within the interior trim.

At the top where the noise is "coming" from, all there normally only the
belt attachment bracket with a height adjustment assembly (if your car is
fitted with one), a spacer (possibly), an anti vibration washer and a main
anchoring bolt to hold it to the pillar. This would be capped with trim.

The clicking could be caused by a slight rubbing or snagging of the trim of
within the height adjuster.

Try taking the trim off and see if that helps.  You could also simulate
"locking the ball bearing mechanism by pulling sharply on the belt when
driving to see if the clicking stops.  At a last resort you could drive
without a belt on to see if the angle of the belt over your shoulder stops
the noise.

Sorry I can't be of any more help. Good luck.

CF