Ninja'd again. I don't really like that armor because from what I can tell, that breathing apparatus is part of the armor. It would look completely ridiculous with any helmet from a different set and the clipping would just be horrible. Hopefully I'm wrong, because I kind of like that armor. Not as much as the regular Advanced Power Armor, and certainly not as much as the Fallout 3 Tesla Armor, but it'd still be a shame if it became unpopular due to that stupid gas mask thingamajiggy.
Uh, the mask and skull are likely not part of the Armor set. It's just something that the guy chose to wear. I don't think the breathing mask is part of the armor, more likely a "glasses" slot item.
Hopefully the armor looks more impressive in person, like the tesla tubes glow and there's a bit of an "energy field" effect around the armor like in F3.
I think this whole thing with the original enclave armor is saying something about the lore- namely that the Enclave developed their F3 armor while at Raven Rock, and left most of their old armor behind, AND, that the Enclave had already incorporated Tesla energy field designs into their armors before leaving for Raven Rock.