A SPECIAL REPORT: BOXING

NEW KID ON THE BLOCK: Orange County, a haven for white-collar workers, has become a twice-monthly host to the most blue-collar of sports. . . . LBNT Pro Sports, headed by Nick Bartlett, started up a second county boxing show earlier this summer at the UCI Bren Events Center. His first card drew fewer than 500. But when the third card was presented recently, LBNT had not only actor Mickey Rourke in an exhibition but a title fight between Darrin Van Horn and John Jarvis. Van Horn defended his International Boxing Federation super-middleweight title with a third-round knockout.