Pam, your phone book ad lists the cuisines of the International's restaurants, which fit with Don's 4 matchbooks:
Japanese = Benihana
Mexican = El Patio
Italian = Leonardo's
Bavarian = Bavarian Inn

So, the missing 5th "foreign" restaurant must be Gourmet cuisine.

I came across 2 matchbooks I have from the LV Hilton days:
-- Barronshire Prime Rib (obviously named after Barron Hilton, so wouldn't have been in the International days.
-- Imperial Room -- I recall that it was LV Hilton's gourmet room for quite a while, but don't know if the name extends back to the International days or not?? It was a really nice place to eat.

So ... just tossing out the possibility that Imperial Room is a possibility ???