ALEXANDRIA, Va. (AP) Reynolds Metals Co. has gone into federal court in an attempt to Reynolds and two of its sub sidiaries asked the court to at tach a $12.5 million check alleged ly being held in this country as payment for agricultural equip ment Cuban Dictator Batista was going to buy before he was over thrown by Castro. An affidavit filed with the com plaint for damages and petition for attachment alleged that the cashiers check, reputedly drawn on a New York bank, is in the possession of Frank M. Austin of Alexandria. Avetin told newsmen, however, he has heard nothing about a suit. “I don't have, nor have I had, any check that belongs to any-