CBS-owned WCBS-TV in New York has bought broadcast rights to "USA Today," the half-hour daily news and features program that is former NBC Chairman Grant Tinker's first syndicated program effort. The station's move fueled speculation that it may start broadcasting Dan Rather's "CBS Evening News" a half hour earlier in order to open the 7-8 p.m. time period to "USA Today" and a game show. But WCBS spokeswoman Jennifer Geertz said Thursday no decision on that has been made. The station in 1986 considered moving Rather's broadcast from its long-time 7 p.m. slot to 6:30 p.m., but dropped the idea after protests from CBS News officials. "USA Today," due to premiere in September, was bought last month by CBS-owned KCBS-TV Channel 2 in Los Angeles, which moved Rather's news program to 6:30 p.m. in September, 1986.