Have you checked the exe file? FalloutNV.exe? check the properties.
Yea like I said it says 1.214 or something similar.
If the mods & weapons aren't being affected, then it does sound like their game isn't updating. Unfortunately I have no help to offer...it sounds like it's a Steam issue. All I can say is to keep trying to update it, see if it finally works.
Or re-install Steam/the game. Maybe something went a little weird with one of the actual Steam (not NV patch) updates at some point.
Poop, I have a bandwidth cap that I just exceeded, so not a possibility.
ZWarden, what country are you from? I'm beginning to suspect it might be a regional issue.
Canada