Rick,
According to the Price Guide those cards are from $75 to $150 each. Not too many of them around.
The 2nd through 5th issue has a riverboat on it but I've never seen them.

Here's a couple of match covers.
The River Queen has no slot cards. I don't know if the casino even existed. The River Queen cover is hard to find.

I'm looking for the new Colorado Belle EC. Do you have an extra?