Digitalage 101

I was playing some matchmaking last night and I saw someone with a full set of mark 6 armor. He was a lower rank than me and I knew it was in halo 4 multiplayer so I was trying to figure out how to get the armor. I heard you have to beat the campaign on legendary to unlock it but I want to be sure. I wanted to beat it on legendary with my friends but they're not getting the game until after thanksgiving break. So the question is, do I have to beat the campaign on legendary to get the mark 6 armor set?