Gaming Pokémon Mystery Gift codes region locked?

[dajavax]

I am a mexican with an american 3DS and an american Pokémon Y. I am currently living in the UK studying.

I saw the Magmar and Electabuzz distribution event detailed here:
http://instore.game.co.uk/fun-in-store/#PokeCharacters
http://www.pokemonxy.com/en-gb/pokemon/electabuzz_magmar_distribution/

I got my code and when I tried to use it it told me: "Your Game Card cannot receive the gift provided by this code."

Does this mean it is region locked? If that's the case, is there any European here willing to help? Though I'm not sure if it's also limited to one for each cart.

 

[jomaper]

One for each game, and region locked, ofc. Doesn't matter where you currently are in the world, if the game is from USA, UK stuff won't work.