The problem with that one, Charles, is in the case of a "sold out" LE that would be put back in play if and when any were returned to a casino. Although these chips would fit your definition, since they would not be available from the original source (since they were "sold out" at the reference time), I don't think that most people would consider them obsolete.

I do like the basis of your definition, but I think there should be a little of that "...if the casino had one in the cage..." language added in.