Firstoff, I dont know if WW2 and/or Korea went down in the Fallout universe..but if they did, dont you think the NCR would have armor more closely resembling what US troops wore in those wars? I mean they look like there wearing WW1 British trench armor for cryin out loud....
Those helmets there wearing were never used by the US armed forces ever...The British wore them in WW1 and WW2 (i believe they rocked them in ww2 but im not 100%)
And the way there pants flare at the thigh makes it look even more like British armor...So what is the deal with that? Shouldnt they be wearing M1 helmets and such?