Armor customization (Halo 4)/Forearms

From Halopedia, the Halo wiki

Forearms
Forearms Unlock (Halo 4) Unlock (Halo: The Master Chief Collection) Skins Unlock (Halo 4) Unlock (Halo: The Master Chief Collection)
Contoured SR-39 Unlocked by default on Season 4 update SHRD Complete Perfection Commendation Unlocked by default on Season 4 update
FOTUS Buying Halo 4 Limited Edition Console Unlocked by default N/A
GV-09 Locking SR-22 Unlocked by default on Season 4 update FRST Pre-orderHalo 4 from GameStop Unlocked by default on Season 4 update
Inner-plated SR-30 Unlocked by default on Season 4 update WEB Pre-order Halo 4 from Amazon.com Unlocked by default on Season 4 update
TOXC Buy the Spartan Scout figure from McFarlane Toys' Halo 4 Series 2 Unlocked by default on Season 4 update
Mark V Buying the Infinity Armor Pack or the Champions Bundle Season 7, Tier ?? N/A
Mark VI Complete Legend Commendation Unlocked by default N/A
ODST Buying the Infinity Armor Pack or the Champions Bundle Season 7, Tier ?? N/A
Outer-plated SR-34 Unlocked by default on Season 4 update RPTR Pre-order Halo 4 from Best Buy Unlocked by default on Season 4 update
BYNT Buying the Champions Bundle Unlocked by default on Season 4 update
RFCT Buying the Didact figure from McFarlane Toys' Halo 4 Series 2 Unlocked by default on Season 4 update
Prefect Buying the Infinity Armor Pack or the Champions Bundle Season 7, Tier ?? N/A
Recruit Unlocked by default Unlocked by default PRME Buying Halo 4 Limited Edition Unlocked by default on Season 4 update
Ricochet Buying the Bullseye Pack or the Champions Bundle Season 7, Tier ?? N/A
Twin-plated SR-9 Unlocked by default on Season 4 update AEON Complete Close Quarters Commendation Unlocked by default on Season 4 update
SWFT N/A Unlocked by default on Season 4 update
XV-27 Shifting SR-48 Pre-order Halo 4 from Best Buy PULS Pre-order Halo 4 from Microsoft Unlocked by default on Season 4 update
CRCT Pre-order Halo 4 from Walmart Unlocked by default on Season 4 update
SLID Buying the Champions Bundle Unlocked by default on Season 4 update