Hunter masts usually support a Main halyard, Jib halyard, and Spinnaker halyard. If you have a roller fuller, it is possible that the dealer who set it up only ran the main halyard, leaving you two messenger lines. These are only good if they come out of the top of the mast. If the sheaves face forward, they are for the jib and spinnaker halyards.
I would be very surprised if the main halyard is not already in place. In the case that it is not, choose the messenger line that has the sheave facing aft at the top of the mast.
Can you confirm that the two lines you have come out of the mast, and not the boom? The reason I ask is because the mast halyards have separate openings on the bottom of the mast and then go to turning blocks on the mast step to lead them aft to the cockpit. I would never expect to find two messenger lines leading out of the same opening on the mast.
