I will have to watch it again but I seem to recall the chips in Vegas Vacation were actually Mirage chips. In that case though, the whole movie almost seemed to be a big Mirage commercial. From the casino host's line "Welcome to the Mirage Mr. Pappageorgio" or Hellen Griswold saying " If you see the Clark Griswold I married tell him we're staying at the Mirage" to Cousin Eddies Huge drink with the Mirage Logo "This has Bigger Flames Then the Red Drink." In the case of Vegas Vacation, there was no secret that they were using the real names of the casinos. In a movie like Casino, on the other hand, they created a ficticious casino. (The Tangiers). For that they would have had to create chips for the movie.

Clark: What can I do with $5.
Dealer: Buy a bullet and rent a gun?

or another,

"I'll tell you what, You give me half of what you were going to loose, We'll go out back, I'll kick you in the **** and will call it even"

I would have actually used the word **** but yesterday I tried to say P***ed and got censored