Halo 3 COS and Warrior arms unlock

Games Halo: The Master Chief Collection
1

I see them locked but they can’t be unlocked anywhere from what I see. We’re they a timed challenge?

2

COS forearms: Season 6, Tier 90. Warrior forearms: Season 5, Tier 88.

3

> 2535452387883664;2:
> COS forearms: Season 6, Tier 90. Warrior forearms: Season 5, Tier 88.

Thanks, I didn’t see the knuckle parts and got confused