You would think that with all the knowledge of everyone here, someone would have heard of Omni frames. Just as dabern states, check the sticker, if it's there. Could be the guy is just trying to drown out his no name frame with nice parts. When you go to see the bike, check the stickers and anything else that may clue you into the frame. And do try to get the price knocked down a bit. And even ask about the frame origins, how he got a hold of it, etc. Basically calle him out on it. If you don't like his answers, move on.