g2222: Please check that you don't already own this game before blindly claiming the key.
Kid_Kidding: FYI: you cannot claim a key on GOG for a game you already have.
g2222 had been referring to the fact that
some (but, not all) GOG games obtained through Amazon Prime Gaming possess unique product identifiers.
One may have previously purchased a game on GOG, but, in certain instances (due to separate product identifiers), GOG will allow for the redemption of an Amazon-sourced code for said game... essentially 'wasting' the code.
Conversely, one may have previously acquired and redeemed a code for a GOG game via Amazon, and, the game
may not be marked as
[Owned], thus allowing for an accidental purchase (in the event that a user had forgotten that the game resides within their library).