If you have it as an option when you pick assassn then yeah, if not IDK how you would unlock it so probably not. Also, on behalf of all MNC players I hereby welcome you to this wonderful game
I think only the people who played doing the PAX weekend got it for keeps, anyone else who didn't sadly I think missed out. Just like the Progear for being a beta tester. TF2 gear I do think is still obtainable as long as you have TF2. The other stuff Holiday included I do think everyone gets, thought I could also be wrong on this as I have no real 'proof' of any of this being right ether...
Only people who bought MNC prior to Feb. 1st got the TF2 gear. Not sure about cardboard tube gear, but I was under the assumption that new players got it automatically.
I could have sworn you made a thread just like this with Eka answering the question. Weird. Anyways there are two versions of the Cardboard Tube Samurai outfit for the Assassin. The one everyone gets and the Battle Damaged version. The Battle Damaged version is exclusive to those who attended PAX East and requires an unlock code to acquire.