no, you dont need a bolt there, a honda tech once told me it was there to help set the tension during the engine assembly process. if you did install a bolt there,i would remove it. as the belts seat, the bearing cannot adjust itsself to the slack introduced and the belt will be loose. i would remove the bolt just to be safe.
the timing belt doesnt take as much tension as an external belt, just snug with no slack or vibration with the engine running is usually enough.