I really don't know anything.
I know Davis Dam isn't far from Laughlin, and I always thought that Davis Dam was the town's name, before it was Laughlin. But...looking at the chipguide, it says the Davis Dam Riverside was open in 1977. Since the Riverside in Laughlin opened in 1966, my theory doesn't make sense.
Then again, the matchbook on the Chip Guide shows the Riverside, and Davis Dam, and Bullhead City...but it doesn't show Laughlin?
The Laughlin Riverside does (or did) river cruises to Davis Dam...don't know if that had anything to do with it?