Secretly Locking Seafall Treasure Chest

My gaming group got Seafall with the intent to play it, and I was looking at the terribly boring cardboard treasure chests that came with it, and I just felt the need to do something more fun, and although I originally planned to secure the lid with magnets, I got carried away and made it have a secret locking mechanism where you rotate the symbol on the top and it locks and unlocks.

I've only finished one of the Seafall symbols so far as I've just finished the prototype build, but I've inclu