So its a completely new game not a remaster of the original 2009 modern warfare 2 it just so happens to share the name because of the popularity of modern warfare 2024s remake, they wanted to let new costumes know that this is the sequel to 2024s modern warfare.

Though finding official confirmation is complex, the reason the guns have different names in the games could be because of an industry-wide shift away from licensing deals with gun manufacturers.