Hey Tyrus!

Old definition of a ducat is a European gold or silver coin. Recent (and this could be pretty old, given the similarity to the sound of both words when spoken), a ducat is the same thing as a ticket (used for entry to an event or use of a service.) The auction description doesn't explain why the piece is a "Lucky ducat", nor does anything on the one-sided scan of the token. Looks like something you'd find in a giftshop keyring.

Bob