The Silver Rush's sign looks a lot like the sign the Golden Nugget used in the middle of the 20th century. The Wrangler moves one of his arms, much like Vic did before 1991. The Atomic Wrangler's exterior sign is topped by a neon cowboy who looks somewhat like the iconic Vegas Vic.
Vikki and Vance's 'death car' and artifacts are on display in the Vikki & Vance's main hall, whereas Whiskey Pete's has an exhibit containing the car and clothing Bonnie and Clyde died in. The Vikki & Vance casino corresponds to Whiskey Pete's Hotel and Casino. Notable similarities include the large outdoor sign featuring a bison/buffalo and the presence of a roller coaster.
The Bison Steve casino is based on Buffalo Bill's Resort and Casino. I'll start with casinos, since you asked about those specifically: The game also contains numerous locations that are parodies of real-world locations.
Here are places that exist in both the game and the real world:
