There is no independent evidence that an altercation took place between Allison and earp.
Word Origin and History for Allison
fem. proper name, a dim. of Alice (q.v.), via O.Fr. Alison. Popular in U.S. as a girl's name from 1990s, but all but unknown there before 1946; it was popular in England and Scotland 13c.-17c. As a surname, it could represent "Alice's son."