I haven't played the final version of the game myself so I'm not sure, but I did a quick search: [link]
If you click the "show spoiler" link, you'll find that those armors are the Tier 2 Human racial armors so if you're playing another race it might not be available for you. It kind of makes sense because, if I recall, the Seraph are a human organization in GW2.
Well, in GW2 all of these can worn by rangers because they're considered "medium" class armor. There were a few armor sets here and there that we designed as tribute to the old professions visually, but there are no armor sets that are restricted to any single profession (or at least that was the philosophy before I left the company).
Were they modeled in 3ds max or maya? Looks fabulous. But I'm looking for the best modeling program to learn. Though I have a free copy of Modo, I think I should just learn that but there are hardly any tutorials on it.
These were made in Maya, with the high res source meshes created in Zbrush. My honest opinion is to go with Maya or Max as they are industry standards. You can use whatever you like, but if you go pro then eventually you're probably going to end up using Maya or Max whether you want to or not.