Braze on or what sort of clamp on a Cinelli frame?
The Cinelli spec for this bike lists it as "clamp on" and your picture definitely shows a clamp on style front derailleur.  

While it does seem like the factory build comes with a Cinelli branded clamp, if the frame you are buying is missing that part, you shouldn't have any trouble with a campy clamp, like this one:



If you are buying a a new campy gruppo, make sure you get the clamp on style front derailleur.  You can find just this part as well on ebay or an online parts supplier.  There are also adapters for braze on to clamp on style derailleurs, in case you found a good deal on a used campy gruppo with braze on front derailleur.