Augustus McRae and Woodrow F. Call may be riding again. CBS is so thrilled with the ratings and advertising revenue that the "Lonesome Dove" miniseries generated that the network is considering a "prequel" about the noble cowboys in their younger days, according to The New York Times. CBS Entertainment President Kim LeMasters said the proposal has been forwarded to Larry McMurtry, author of the Pulitzer Prize-winning novel that gave birth to the miniseries. "He is being asked the question right now," LeMasters said. CBS also is planning to rerun the eight-hour series this year.