Atlantic City Police Sgt. Monica McMenamin says the men took nearly $200,000 in men's and women's Rolex watches. The haul was previously estimated at $500,000.
The theft was reported at about 8:45 p.m. Monday amid the hotel's 10th anniversary celebration.
McMenamin says the men ran from the store before taking off in a dark-colored vehicle. She says they did not use or threaten to use weapons.
Police still are looking for the three.
The Borgata issued a statement saying it is "fully assisting and cooperating with law enforcement in their efforts to find and prosecute the people involved." The Borgata opened July 2, 2003, as the first new casino in the resort town in 13 years.