Fred, your question kind of faded but it's worthy of some more discussion. As Pam said:
"The oldest five, in their original buildings, sounds like a good question for the Las Vegas Advisor Question of the Day ! Just off the top of my head, I imagine that the El Cortez wold be one. The Golden Gate building was built in 1906, though it didn't have a casino at that time and wasn't called the Golden Gate. Part of the original Riviera is still standing, and it was built in 1955. Railroad Pass received the 6th or 7th gaming license issued in Clark County, in 1931, but I don't know if any of the original building is still standing. Of course, some of the small town or Reno and Tahoe casinos might be in the five oldest...maybe the El Capitan, which opened in the early 1950's? Good question!" Who else has some thoughts.