It doesn't exist, but neither did Hollywood take liberties with history.
The Mint was an actual casino in downtown Las Vegas. It opened in 1957 on Fremont Street between First and Second, next to Binion's Horseshoe. A 26-story 296-room hotel tower was added in 1965 at a cost of $6 million.
The Mint was made famous by the Mint 400 off-road race (see QoD 5/7/06), which was the basis for Hunter S. Thompson's book Fear and Loathing in Las Vegas.
The hotel-casino was bought in 1989 by the Binions for $36.5 million, at which time the Mint became the Horseshoe West. All the Binions had to do was cut out a through passage in the shared casino wall to incorporate the Mint into the Horseshoe. For a long time, the two casinos were a contrast in '50s and '60s design and decor, but today -- nearly 20 years later -- the old Mint is pretty much forgotten (aside from its clock -- see QoD 7/11/08), now just a part of Binion's.