According to the oneworld
website, you receive preferred seating "in accordance with the individual policy of the oneworld member airline operating the flight." According to
aa.com, you do qualify for preferred seating, but this is a consistent problem across oneworld. Many OW airlines tell me that they don't pre-assign exit row seats. Others tell me that they won't do it for another FF program. Others have told me it's only for OW emerald members.
/cp