sure!
mostly i suggest the red/yellow/green coloring because a lot of people already associate those colors with priority (look at stoplights, notifications for websites, etc.) here's the setup on trello: notice that the priority labels always appear as the first label.
trello actually is set up by default so that the red/yellow/green labels are above all the other labels so they appear first on cards:
obviously you don't have to use this convention--but just a small suggestion for some even easier legibility at a glance.