Gamestop updated the image for the Spartan Locke HUNTER-Class Armor Set. Halo 5: Guardians Pre-Order Bonus content is not exclusive. You can earn Pre-Order bonus content in-game through the REQ System.
As predicted, Josh Holmes ( Studio Head for Halo 5: Guardians) confirmed via Twitter that Pre-Order Bonus weapons, skins, etc… for Halo 5: Guardians can be earned through regular gameplay. Pre-order just guarantees access to them day 1.
HUNTER-Class Helmet: Though still considered a prototype implementation, the HUNTER’s sensor suite enhances situational and threat awareness.
UPDATE: Josh Holmes, Studio Head for Halo 5: Guardians has confirmed that the Spartan Locke Armor Set is not exclusive to those who pre-order from Gamestop – it can be unlocked through normal progression.