It should as long as you have Bravia Sync enabled on the TV.

No, the Sonos Arc has no display, and does not send any overlay back to the TV set. Whether or not your TV displays a volume indicator or not depends entirely on how the TV manufacturer has implemented their version of CEC/ARC. It has nothing whatsoever to do with Sonos. 

On both my old and my newer Samsung volume up or down is displayed on the screen. I have a gen ! Beam connected via HDMI.

Volume up/down, sure, but the OP wants the actual volume level I think (ie a number).

Most who ask a question about this do, but OP isn’t very clear in what he expects.