The USCG Navigation Rules, Inland Waterways, Rule 25, "vessels under oars" allows you to display traditional red/green nav lights at the bow with a white light at the stern while underway at night, or you may display a white light at all times, or you can run dark but have a white light at hand to avoid collisions.
The more light the better, especially on busy waters at night. But common sense tells me that red/green nav lights 6" off the water will not be seen as well as the the super bright white LED light on the end of a 3' fiberglass pole that is sold for kayaks.
FWIW, if you display navigation lights that violate the specifications of Rule 24, (red/green facing to your stern is a violation) you open yourself up to liability if you are struck by another boat. And I'm not strictly speaking of legal liability. If you display nav lights in violation of Rule 25 you might get run over and killed by a powered vessel who was relying on you to have a proper and legal display of lights.
And if I haven't been clear enough, a vessel displaying one white light and no red/green navigation lights tells other boaters that you are either an anchored vessel (Rule 30) or are a HUMAN powered vessel (Rule 25). Why send a mixed message with red/green nav lights?
http://www.navcen.uscg.gov/pdf/navRules/navrules.pdf