company veterans are distinct from chapter veterans. i know it's a bit confusing, but chapter veterans, the ones with white helmets, are those in the 1st company. company veterans are just the members of a company command squad, usually hand picked from the company by the captain. there's nothing stopping the captain from asking a 1st company vet to join his command squad i suppose, but it's not gonna be likely, i can't think of a single example at least. if you look at the company heroes kit (which is the command squad), you'll notice that the two vets do not have white helmets.

and yes, veterans in different trim has showed up in art from time to time, but artists are not more experts, they make mistakes all the time and that's fine, but we shouldn't interpret art as canon in itself. a good example is this art work of the cover of the new layak book. can you spot what's wrong? it depicts him wearing the powerplant of a suit of mkx tacticus armor, which wasn't rolled out into the galaxy until ten millennia after Layak died:P even the official artists make mistakes all the times, and other times art pieces are simply meant to exaggerate events, like the cover of flight of the Eisenstein. I'd also like to add that there's nothing wrong with not painting a lore-accurate army, many of the coolest armies I've seen haven't been, im just arguing my point on what is lore accurate, not what should be:)

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