Sept. 13, 1961 - Dick Gregory, who won quick fame last spring as the first Negro comic to succeed in metropolitan cabarets, is back at New York's Blue Angel. Mr. Gregory has expanded his target range. In a new string of jokes tried out for the first time this week, he refers to the German, truck-borne escapees as the "East Berlin Freedom Riders." "They are people who push the gas pedal down to the floor and don't look right or left," he says. "In New York, we call them cab drivers." Regarding New York City's crime problem, he says: "I'm glad they've cut the police working week down to 40 hours. Now if they can just get the hoodlums to keep the same hours."