It will only be the actual exit rows which get the green arrows.

On the A320 in ET I can't see any seats marked as "standard extra legroom seats".

In terms of the A321 it should be the same, so only actual exit rows showing as the green arrows, and no "standard extra legroom seats".

EDIT: actually on checking one of my A321 bookings all exit row seats are green but only some have a green arrow