I don't particularly like the designation of illegal for these places, but don't have a better all-encompasing term to suggest. Un-licensed implies that there's someone to issue licenses, and in many cases there wasn't. Supporting the local police so they would leave you alone was all the license you needed.

Regarding chip suppliers and their willingness to ship anywhere, remember that things were different in those days. Not only would they sell chips and dice to anyone, many openly sold loaded dice, marked decks, and other supplies to assure the "advantage" of the buyer in running his games. Their explicit catalogs are collectibles today.