Is the winterized power armor you get after OA invincible? I've been blasted up a TON and it hasn't needed any repair - always perfect - if it is indestructible, how did they have this kind of technology during the war? Seems like a bit of a stretch right?

The armor has an item health of nearly 10 million HP while the helmet has nearly 1 million HP. This makes it virtually impossible to damage either the armor or the helmet. It is probable that the developers accidentally placed the wrong version inside the cache.

So more of a glitch I guess than something that could be considered canon- we're not to assume the Americans had indestructible power armor ha

The Winterized Power Armour is awesome.
I don't care why it's indestructable, I am just glad it is.
I think it is either a glitch or it is meant to be like that because it was super special armour.

Whatever it is it is awesome.