I use water based paving paint for anything I care about that will be in the sun. Looks ordinary when brushed or rolled, but good when sprayed.   Lasts at least 6 years before turning chalky which gets on your clothes and skin but is still protective.  I have unpainted bits on El that I don't care about that have been in the sun (South East Queensland, pretty sunny) for several years and are still sound.  Eventually the resin in the top layer or 2 disappears and it needs another coat.  If it is loaded, the affected layers need to sanded off and replaced.  

If the T is not stored in the sun, and not sailed every day, then it should be fine with no paint.  Your call on exposure, looks and non slip.