Rich Burgel posted a couple of matchbook covers, from the Thunderbird, a few days ago. One of them had the phone number 5000. The other had the phone number 5100, which is the number I'm familiar with for the Thunderbird.

Since I was playing with phone book scans, I searched for the phone number "5000". It showed up for the Bank of Nevada, in several phone books. It never showed up as belonging to the Thunderbird...