Halo 4 Specialisation email?

Hey guys, I’m just wondering about something. I got an email about a month ago, containing the code for the Halo 4 Specialisation Unlock, I activated it and everything, but it hasn’t unlocked. My question is, does it unlock once I hit level 50 or was it suppose to unlock straight away? I’m a little confused and just want someone to clear this up.

Cheers! :wink: