If it is a Specialissima, then 1963 or earlier based on the two wide chrome bands on the seat tube. But is it? The crank looks wrong, the decal on the downtube right after "Bianchi" is hard to read but doesn't have the shape of the word "Specialissima". Of course it also looks like some of the components have been changed (stem, bars) so maybe the crank was too.