Very nice looking bike. You did well! Marker of a bike in fantastic shape - frame reflected in the headset!
I'm not sure you can date yours by presence or absence of the Corsa Extra sticker. I have the '85 brochure and the Criterium is also shown in that paint scheme with SLX tubing. Croce D'Aune came out '86 or '87 (I think) and that might help date yours if the BB serial number doesn't.
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N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '82 Colnago Super, '95 Gios Compact Pro, '95 Carrera Zeus, '84 Basso Gap, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, '84 Paletti Super Prestige, Heron Randonneur