Round tubes, the style of the stay/dropout joints and the internal brake cable suggest that it's a Super Piu but it could be a Superissimo or an Altain. Trying to identify a refinished Colnago frame is a nightmare, especially as the factory was open for varying models for special orders. To my eye there's more 'wrong' than 'right' about the frame, in no particular order there's no chain stay bridge which would be expected with a BB shell of that style, there's a distinct lack of branding on the frame (nothing on the BB shell, seat stay top eyes or seat lug) and most tellingly the seat stay brake bridge boss is a cylinder rather than the more cubic style I'd expect to see.
That doesn't mean it not a Colnago, at times there were so many different models (some very short-lived) leaving the brand factory and those of the sub-contractors that I doubt anybody can identify them all.