Related Clues:

• Like many valuable stamps
• The Gunners initially rusty, especially having few matches?
• Steak temperature near 'still mooing'
• Order that's not well-done
• Steak may be so uncommon
• Unusual pink
• Valuable to collectors
• Like a 1913 Liberty Head nickel
• Like having a 17-Across that lives up to the expectation created by the culture industry's image of romance
• In very short supply
• Undercooked, as meat
• "Still mooing," as steaks go
• Pinker than medium
• Roast beef order
• Not often encountered