Looks Sunfishish to me
Whatever is shown on the Craigslist link looks a lot like a Sunfish sail. Sunfish have no traveler, per se. Instead, there is a bridle - located at the stern of the boat. My Sunfish has a cable with a loop in the middle of it. It appears the newer models do not have that loop. The bridle is attached to the deck by eyestraps and screws.
See
http://www.sunfishdirect.com/sunfish.php?p=sunfish_deckview
The mainsheet clips on to the bridle, then runs through two blocks from the aft to around mid-boom to your hand in the cockpit.
No matter how it's attached, as long as you connect the mainsheet to the bridle (traveler), through a couple boom blocks, and to your hand, you should be good to go.
Have fun!