All codes ARE working (worked for me), hope you like it =)
Credits to: http://halo4arg.wix.com
1- Completing the Campaign on Legendary also unlocks Mark VI armor set and LEGENDARY (orange) Visor color.
2- To track your 1000 matchmaking war games, DONT SEE
YOUR SERVICE RECORD FROM HALO 4 GAME.It also counts the matches you enter on mid-battle (and those matches dont count to unlock the helmet). use your Halo 4 STATS from the waypoint website to track you matches.
3- You dont need to WIN 1000 matches, just play from the begining to the end.