A student who was docked a grade in history class for his absence while he met Soviet leader Mikhail S. Gorbachev said he will appeal to Gov. George Deukmejian. Andy Leman, 18, a senior at Del Oro High School in Loomis, said the local school board refused to overrule his history teacher, Rolf Moeller, whose policy is to lower a student's grade by one point after five days of unexcused absences. Leman spent 11 days in Moscow and Washington in November and December and was among a group of youths who gained an audience with Gorbachev during his visit to the United States in December. According to the teacher's policy, his A-grade will fall to a B. But Leman feels the grade is crucial for college entrance and said he will use the upcoming semester break to contact the governor and the American Civil Liberties Union.