AT THE 1992 OLYMPICS IN BARCELONA the U.S. basketball team will for the first time include NBA pros. This weekend (Sat., Sept. 21, 5 P.M. ET) in a live show NBC will unveil the roster, a lineup expected to include Magic Johnson, Larry Bird, Patrick Ewing, Michael Jordan, Charles Barkley and other perennial all-stars. Maybe we could extend this trading-up tactic to other international athletic events. We'll see how good those Taiwanese tykes are next year when they step out of the dugout at the Little League World Series in Williamsport, Pa., and see Roger Clemens glaring at them from the mound.