I have never been there, so I can't say for certain. My first thought was that it's just another part of NC, so OC should be good to go except in the usual free kill zones. Then I remembered that a lot of that area is designated as wildlife refuge and parks so I pulled up google maps and, sure enough, a lot of the outer banks are colored green. And that is where the line gets a little blurred for me. If it is a national park, then you're good to go (except for the federal buildings). If it is a state park, then you're not so good to go - you'll have to conceal. I'm not sure about national wildlife refuges, reserves, and the like.
... was wondering how friendly OBX (Hate that term!) is to open carry.
If you dislike the term, then simply use the actual words: The Outer Banks. Letters and words are free - use them!