Related Clues:

• 39-Down, e.g.
• Of interest to collectors, say
• Chophouse request
• Atypical
• Quite unusual
• Like a 1943 copper penny
• Out of the ordinary
• Facing extinction
• Answer to a waiter, sometimes
• Nearly extinct
• Still pink
• Uncommonly good
• Once-in-a-lifetime
• E.g., e.g.
• Like hens' teeth, so to speak