I found this book/kit by Valerie Garwood. Can't be certain because the picture isn't detailed enough, but it might be the "coin" in question.
Lift the Lid on Pirates Kit
by
Val Garwood
Lift the Lid on Pirates Kit
Discover high-seas adventure, build your own pirate ship, and navigate with a 16th-century compass! Explore history through the fascinating lives of real pirates! This kit includes a fully illustrated booklet, a pirate ship model to construct, a quality replica gimballed compass, pirate bounty stickers, and more!
Here is what this treasure chest contains:
A treasure box with a secret drawer
A working replica of a 16th-century ship's compass
A model of a pirate ship for you to make
A realistic metal replica of a piece-of-eight Spanish coin
A facsimile map of the Spanish Main
Nine stickers to use on the map or elsewhere
A length of rope with which to practice tying sailor's knots
The 24-page full-color booklet "Lift the Lid on Pirates" which contains the following:
* What is a Pirate?
o Early Sea Robbers
o Where Did Pirates Operate?
o Pirate Myths
* The Mediterranean
o The Barbarossa Brothers
o Oared Galleys
* Pirates of the East
o Indian Ocean
o South China Seas
o Thomas Tew and Henry Avery
* The Spanish Main
o Spanish Ports in the Americas
o The "Golden Age" of Piracy
o Using Your Chart of the Spanish Main
* On the Attack!
o Pirate Weapons
o Torturing Hostages
* Pirate Ships
o Repairs and Maintenance
o Making Your Model Ship
* The High Seas
o The Astrolabe
o Avoiding Shipwreck
o Using Your Compass
* All Aboard
o Pirate Flags
o Reading Your Coin
* Daily Routines
o Disease and Medicine
o Food and Drink
o Tying Your Pirate Knots
* Pirates on Trial
o Pirate Trials
o The End of Piracy's "Golden Age"
o Mary Read and Anne Bonny
* Fact or Fiction?
o Long John Silver
* Piracy Today
o Modern Pirates
* Glossary
A cardboard treasure chest packed with assorted items, 8 1/2” x 5 1/2” x 4 1/4”