Lancer
From The Quentin Tarantino Archives
Lancer is a TV series (IMDb) featured in Once Upon A Time in Hollywood. The character of Scott Lancer (Wayne Maunder) is played by Luke Perry in the film. His half brother Johnny Madrid is played by Timothy Olyphant.
Episode 1 "The High Riders": Faced with continual raids by the Pardee gang, California rancher Murdoch Lancer seeks the help of his estranged sons: dapper Bostonian Scott Lancer and border-town gunslinger Johnny Madrid (IMDb).
To Be confirmed: In the Tarantino Universe, it's possible that Rick Dalton won the part of Day Pardee over Joe Don Baker for the pilot episode of Lancer.