Genius Bonus examples in Once Upon a Time in Hollywood.
- Rick is essentially a less forward-thinking version of Clint Eastwood, who after his big break on the Western series Rawhide ended did see the wisdom of doing Spaghetti Westerns, launching himself into a legendary movie career. Another parallel: both actors appeared in violent World War II movies (Where Eagles Dare for Clint, The 14 Fists of McCluskey for Rick).
- Alternately, Rick is an alternate Burt Reynolds. Like Rick, Reynolds worked for a long time in TV (appearing in 50 episodes of Gunsmoke and various guest spots) before moving on to junky B-movies mostly filmed overseas before he became a movie star with Deliverance. Indeed, the episode of The F.B.I. that Rick appears in has him replacing Reynolds in real life, while James Marsden was originally supposed to appear as Reynolds in the film before his role was cut.
- Rick Dalton's agent has him sign up to work with Sergio Corbucci, the "second-best" director of spaghetti westerns. Corbucci is a real figure, and the director of The Great Silence and the original Django westerns starring Franco Nero.
- In the climactic final sequence, one of the four Manson Family members gets cold feet and drives away, abandoning her co-conspirators. If you're well-versed in the details of the real Tate-LaBianca murders, this detail will seem a bit more meaningful. The woman who drives away is Linda Kasabian, who really did have second thoughts about her role in the murders. In Real Life, she tried to stop her co-conspirators after being asked to serve as a lookout, and later testified against them in court.
- The dumpster diving Manson Family girls sing a song written by Charles Manson: "Always Is Always Forever."
- Cliff's character as a stuntman alludes to Donald "Shorty" Shea, a former stuntman who worked at the film studios that became the Spahn Ranch. He worked as a bouncer for the Ranch when Manson and his Family occupied the place, and Manson eventually murdered him, personally (with a pipe according to one witness), on August 26, 1969. His body was dumped and not discovered until 1977.
- When Lee is talking about Joe Louis, he makes a point to clarify that he's not talking about "that white kickboxer asshole." This refers to Joe Lewis, a martial artist with whom Lee trained and would have cast in Way of the Dragon before they had a falling out and apparently never spoke again (although this would happen several years after the point the movie is set).
- The last shot of James "Jim" Stacy is him driving off on his motorcycle. Stacy's promising career would be derailed when he and his girlfriend were in a crash. Stacy's girlfriend died in the accident, while Stacy survived as a double amputee.
- Speaking of James Stacy, given what we know about him now
, there's probably a reason Johnny Madrid and Trudy's character don't have any scenes together on the Lancer pilot. - When Sharon is trying to convince the people at the movie theatre who she is, she looks a bit put out when she's told she's "the girl from Valley of the Dolls." Any Sharon Tate buffs will know that she hated both the film and the book it was based on, and only did the film knowing the book's bestseller status would make it profitable. She was also known for being very self-deprecating about her status as Ms. Fanservice, which is referenced when she clarifies that she plays "the one who ends up doing dirty movies."
- Another Valley of the Dolls one. When the ticket guy is running through the cast members, after Patty Duke, he says "the girl from Peyton Place" (meaning Barbara Parkins). At that time, Barbara Parkins was so popular, they were considering giving her a spin-off titled 'The Girl From Peyton Place'.
