Baltimore-based Sinclair Broadcast Group Inc. is finally building its long-sought TV duopoly in Buffalo, N.Y. The company last Friday said it will pay $51.5 million cash to Grant Television Inc. for the WB affiliate in that market, the nation's 44th-largest. Sinclair already manages WUTV(TV) Buffalo and says it earlier filed with the FCC to acquire that station, a FOX affiliate. (Sinclair sold wutv last August but held an option to buy it back.) There had been a third station in the picture: Sinclair had won FCC approval to buy noncommercial WNEQ-TV as its second station in Buffalo. Commission approval was reiterated this past April, despite protests that the public station should not be turned over to a commercial broadcaster, according to published reports. In any case, five months earlier, Sinclair had abandoned its plans to buy WNEQ-TV for $33 million. WNYO-TV was in the news last August after the FCC fined it $14,000 for 24 violations of children's ad limits. The station in April won the right to air several Buffalo Bills football games and ancillary programming.