"The Awful Truth." RCA/Columbia. $59.95. As in another marital farce three years later ("My Favorite Wife"), Cary Grant and Irene Dunne were matched with a sparkling Leo McCarey script for this 1937 screwball comedy. Dunne was a strange choice for such comedies, her eccentricity seldom as convincing as her sophistication. But here she's fine; the scene where she embarrasses Grant by pretending to be his crude sister is one of many hilarious moments. Two awful truths, however: 1) much of the humor comes out of wealthy arrogance or at the expense of likable people, 2) the tape transfer is too grainy.