interesting frame: it does have the 3-descending-size holes in the lugs, but that seat cluster is not the classic Cinelli, and the sloping forkcrown has no reinforcing tangs...so I doubt it's a Cinelli SC (but I'm not an expert by any means). But whoever did that "shot-in" treatment of the seat stays had some skills, and the lugs look well finished, so I'd guess it's from a high-end builder. Have you checked the interior bottom of the steerer for "rifling"? Is the BB definitely Italian threading?