Its interesting that the "W/B1" is in the nomenclature on the data plate, since the kit is designed to be modular and only fitted when necessary. Thanks for posting these, as I think these are the only pictures I've seen of an actual US Army vehicle with the B kit doors rather than the Frag 5 doors.
Now its possible to compare the 2. Compare the Frag 5 doors for the second generation ECV vehicles below with the doors above (click for hi-res):

One can see clearly, especially with regards to the window framing, that they are not the same.