Horrible Secret of Monhegan Island - Mint in Plastic! Call of Cthulhu Grenadier

Description

Call of Cthulhu Adventure Module from Grenadier Models, who promoted their CoC miniatures with a couple adventures.
Cover says "Approved for use with Call of Cthulhu by permission of Arkham House"
Maybe it was approved by Arkham, maybe by Chaosium. Who knows?
Another thing I don't know is how good the adventure is, because this module is unopened in plastic. One corner slightly bent or pinched on back cover. Doesn't show on front cover.