Not being from the area I'm just speculating that no one has provided verified information to the RR database. Also, the licenses don't appear to be in the name of the casino, or the ownership groups, so until you figure out who's name the license is in it might be very difficult to find. For example, the ownership group is based in Chicago and may have gotten a nationwide license from there which wouldn't show up in the PA database or FCC records under the casino name.
I've run across a number of business over the years that I never could find in any listing or doing searches. Also, I've found a number of casinos (and a lot of malls now) have begun using encryption, so you might not hear anything helping you identify the user or usage of certain frequencies. If you verify the frequencies and usages you definitely should submit them to the RR database so others can find them.