A group of off-duty uniformed firefighters got into a drunken bare-knuckled brawl at a Bronx bar on Wednesday — just hours after they were honored for their heroics by the mayor and fire commissioner, the Daily News has learned. A racial slur thrown at a black firefighter sparked the fight inside Billy’s Bar near Yankee Stadium between Bronx’s Rescue Company 3 and members of Ladder Company 49 and Engine Company 68, which share a stationhouse in Highbridge. “They were drinking since 11 a.m.,” said a source with knowledge of the incident. “They show up at the bar after the medal ceremony and they got out of hand. The ladder and engine guys were fighting with the Rescue 3 guys.”