I can't find any internet reference to a Monta Club. Maybe someone can do better. But perhaps this Monta club, wherever it was located, never actually opened. Chips were ordered but not used. That would explain why a quantity of them, in different colors, now turns up all in "new" condition. If that can be proven - the value of these "new" chips would not be much at all. Not trying to insult the Lady or you!
A difficult task but check out all state gambling commission records for Casino Applications or Inactive Casinos?? Monta sure sounds like something in Montana.