Sadly, even mentioning server firsts brings out the people who think that being competitive in any shape or form is a bad thing. Some people enjoy being the first to do something on a game as the content comes straight from the oven and beta kills don't count, which I can't see why people think doing it in beta was a big deal. The servers were not the same despite similar names, everything was wiped, and stats/talents worked differently so saying it was done first in beta shows that you are incompetent. I will bring out my own responses on the matter though.
My guild got the server first on SD-0 on Corellian Run on the 3rd day (The 5 people who space-barred everything were around 25 at the time on the server and no one was above 20 aside from them). I was on most of the time and so were my guildmates all hours of the day and they didn't see anybody talking about fighting him, other than the fail groups of level 14s.
I can't say at this point how the other world bosses are faring on my own server but they have more than likely fallen so you may not have a server first. Generally content like that is downed within days of it coming out when everyone gets to the level for it.
There's no reason to have "server firsts" other than flaunting your epeen. You can argue it however you want, but it's the truth. Two years from now, no one will give a crap about who killed what first, but I will guarantee you that you will be eager as hell to say "Yeah, me and my friends were the first to kill this" as if it actually mattered to the person you were talking to, and no doubt with the idea that it somehow gives you some sort of massive nerd-cred and the illusion of superiority.
Believe it or not, having a server first, especially on raid content is a huge deal for raiding guilds, though I bet you have ever been a part of a decent one. Being able to show a server first on your guild's "banner" means that your guild gets a lot more attention and it shows the community that you are part of a really really good guild.