Although the plot is mostly fiction, Wyatt Earp and Tom Mix were real-life friends. After Earp retired from law-enforcement, he and his wife drifted around, eventually setting in Los Angeles, where he and Mix met. Mix tried to get Hollywood to produce a movie about Earp, but they weren't interested. Earp was hired as a technical consultant for movies starring Mix and William S. Hart. When Earp died in 1929, Mix and Hart were his pallbearers.

According to "James Garner: You Ought to be in Pictures", Garner said, "I'd never work with Bruce Willis again. I did that Blake Edwards film with him, Sunset (1988). Willis is high school. He's not that serious about his work. He thinks he's so clever he can just walk through it, make up dialogue and stuff. I don't think you work that way".

Wyatt Earp died on January 13, 1929, a few months shy of his 81st birthday. James Garner was 60 in 1988. Garner previously played Earp in Hour of the Gun (1967).

John Fountain portrays his real-life grandfather, actor John Gilbert.

Bruce Willis, who has top billing, has less screen time than, James Garner who received second billing.

This is the second of two movies that James Garner made with Blake Edwards. The first was Victor Victoria (1982).

The regular catchphrase heard throughout the film was "Give or take a lie or two".

Some movie posters featured a blurb that said, "They broke every rule, loved every woman, took every risk and solved the most shocking murder in the history of Beverly Hills. And it's all true. Give or take a lie or two".

The movie takes place during Hollywood's transition from silent films to "talkies."

Blake Edwards' grandfather, J. Gordon Edwards, was a real-life silent era film director.

The picture features various stunts from the silent-film era.

Alfie Alperin was loosely based on Charles Chaplin. Like Chaplin, Alperin was a comic actor who became a director, producer, and studio head. Alperin's screen character of "The Happy Hobo" was based on Chaplin's "The Tramp".

The script was based on an unpublished book by film and television director Rod Amateau, who is credited for the film's story.

The film features a fictionalized sequence of the first Academy Awards Ceremony.

In real life, Tom Mix never portrayed Wyatt Earp on screen.

James Garner and Dermot Mulroney have both played private detective Jim Rockford. Garner starred in The Rockford Files (1974). Mulroney played the role in The Rockford Files (2010).

When Tom Mix and Wyatt Warp land the plane, they're met by two cowboys. The one on the left of the screen, Cowboy Henry, is Jack Garner, James Garner's real-life brother.

Julie Andrews was supposed to play Christina Alperin. Andrews, who was 53, refused to play a woman with a grown son.

The film is Dermot Mulroney's feature film debut.

Second of two movies that actor Bruce Willis made with director Blake Edwards. The first was Blind Date (1987).

The film-within-a-film that Tom Mix was to star in and Wyatt Earp was technical consultant on was "The Lawman".

Theatrical film debut of Richard Fancy.

The film's epilogue says, "...and that's the way it really happened. Give or take a lie or two".

The plot is based, very loosely, on the death of Thomas H. Ince aboard William Randolph Hearst's yacht.

Mariel Hemingway appears in drag.