City and business leaders have won the right to place an attractions sign at Exit 17A on Route 24 touting the statue honoring famed boxer and native son Rocky Marciano and Brockton High School’s Marciano Stadium. The Metro South Chamber of Commerce and the committee that orchestrated the statue’s creation — a gift of the World Boxing Council — asked the state Transportation Department late last year to add the sign to help promote the new attraction. Officials at the time said the statue lacked regional significance. But after local objections, the department announced a change of heart earlier this month and has agreed to allow the addition of a placard to the sign located near the entrance to Belmont Street. Mayor Linda Balzotti has said the sign will be instrumental in jump-starting tourism. With one goal met, chamber and city officials are now asking that Route 24 be renamed Rocky Marciano Highway.