I remember being excited about the early magazine ad with the "23rd century odyssey now" tag line (http://i31.tinypic.com/2rcx6hg.jpg
) in which the writing credit was "Screenplay by Gene Roddenberry and Harold Livingston" - I've never seen an early ad for a movie that had such a drastic difference in writing credits from the released film. Has any thread here addressed this?]
The final writing credit was the result of a WGA arbitration between Roddenberry and Livingston (the latter got full credit for the screenplay). Alan Dean Foster also used the arbitration process to receive story credit.
This kind of thing happens from time to time, and is occasionally reflected in early marketing materials. Chris McQuarrie was credited with co-writing the screenplay of Mission Impossible: Ghost Protocol
on early trailers; Ed Norton was credited with co-writing the screenplay for The Incredible Hulk
on early poster art
as well. Neither were credited in the final films.