Ramon Lopez
An old gag in Eastwood movies is a relevant name on a wall behind the actors. E.g., "Kyle" (Eastwood's son) spray painted on a wall in the first Dirty Harry. (Also "Play Misty For Me" showing at the theater across the street.)
In The Rookie we see several times on the wall in the Mexican bar a wrestling poster prominently featuring "Ramon Lopez" and his opponent "Mundo" (the world). So who is Ramon Lopez? I can't find any connection to Eastwood or Sheen. We know Sheen's father is Ramon Estevez, not Ramon Lopez.
Marco Rodriguez, the actor who played "Loco" in The Rookie also played a character named Ramon Lopez in an early episode of NYPD Blue. Other than that I can't find any connection.
There was a real Ramon Lopez who wrestled in the Midwest back in the '60's and '70's, sometimes billed as "Killer Lopez." But since this movie takes place in Los Angeles in the '90's it doesn't seem likely to be him.
The poster is featured so prominently it just has to be a gag. Anybody have any thoughts?