i was told that we would get the classic helmets req pack if we watched the xbox stream on mixer during the xbox press conference, well my account was linked to mixer and i watched the entire stream but i wasnt awarded the classic helmets req pack at all
Me too 
You can find all the details about the MixPot reward in this thread:
https://www.halowaypoint.com/en-us/forums/6e35355aecdf4fd0acdaee3cc4156fd4/topics/watch-the-xbox-e3-stream-for-classic-helmet-pack/b3bcc500-a991-41cf-90ff-bae8370ade80/posts