Now, I know lots of you readers don't care about world first kills anyway (and you've got a point-- the only down that matter is the one you do with your guild), but lots of players believe there is value in being the first guild in the game to down a boss, and certainly the best guilds in the world work really hard for that honor. But technically, a boss isn't really "done" until it reaches the live realms. Then again, it usually isn't "done" yet anyway even after that.
Personally, I don't think they do count, which is one reason why we haven't yet reported them on this site. I have to applaud Vis Maior and the other guilds for their hard work, and I'm definitely impressed by what they've done, but this content isn't done yet, and in terms of documenting who got there first, my opinion is that we need to wait until after the bosses hit the live realms. You readers disagree?