They had to use british issue snow smocks, because the US didn't actually have any of their own during the battle of the bulge.

But that would actually mean making more than one variant of skin, relic would rather just add a sprinkle of snow to the existing skins and a pair of gloves
Relic really bummed out on the detail starting with western front armies
Lets be honest for OKW, USF and UKF their winter skins are terrible compared to the wehrmacht and soviets with Volkgrandiers and Jaegers getting different winter skins everyone else gets a bit of snow on their pants and maybe a scarf
Then if you look at the machine gun crew for the mg 34 and Vickers or at gun crews for UKF, USF and OKW and the artillery crews for the pack howie and the leig you'll notice relic just reused the same model for the frontline infantrymen (Riflemen, Volksgrenadiers and Infantry Sections) so I dont know why they got lazy did they fire some of their team or something as someone who really loves detail to visuals these disturb me deep down inside