Kim Darby rose to fame as the young woman who asks John Wayne to help her avenge her father's murder in "True Grit" (1969), but while Wayne won an Academy Award for his efforts, Darby's spunky quality did not translate into ingenue status and she proved hard to cast. By the 1980s, her work had become sporadic.A Hollywood native, Darby began performing as a child (billed as Derby Zerby) with her parents, who were known professionally as 'The Dancing Zerbies'. She was a teen-ager when she appeared as an extra in the film "Bye Bye Birdie" (1963) and made her speaking debut on an episode of the TV