CBS – For the first time since he joined the Miami Heat, LeBron James’ team is an underdog in the NBA Finals. The Western Conference champion San Antonio Spurs opened with a -120 moneyline (5-to-6 odds) to win the NBA Finals Sunday, according to Sportsbook.com. Some books have it as high as 135, and that action could increase before Thursday’s Game 1. San Antonio also opens as a four-point favorite to win Game 1. While -120 isn’t exactly breaking down walls in favor of the Spurs, it does show the doubts about the two-time defending champions as well as the…