"You know, we were able to talk to some people and you get the 'two cents' of what Los Angeles was like back then," said Brolin. "And for me, you know, having so many generations having come from California, it was nice to learn that history a bit. And it's fun just to kind of delve into this era."
Ryan Gosling, who is part of this "gangster squad," agrees. He has several scenes with Emma Stone, whose character has ties to the mobster mastermind.
"It's just great dialogue, you know? Will Beall, the writer, just wrote this script that's just full of this great, great dialogue," said Gosling. "All of us were excited to say it."
"I don't know if it's the way the writing was then or what, going from silent movies to where you could just really talk as much as you want, and so they did. It was like 'rat-a-tat,'" said Stone.
"Gangster Squad" was originally set to be released in September, but the film included a scene of a violent shooting inside a movie theater. Out of respect to the victims of the deadly Aurora, Colo. shooting spree, the film was moved to a January release. That particular scene is no longer in the movie, replaced by a gun battle scene that takes place in Chinatown.
"I think that that was a good scene, but I think it was so kind of eerily paralleling what had happened, I mean just like almost to a 'T,' that there was just no possible way you could keep that," said Brolin.
"Gangster Squad" is rated R and opens Friday.