I saw that listing and my sense is that it is a "Fauxnago" . I'm not aware of Colnago ever making aluminum versions of their carbon frames and applying the same name. The Extreme Power is a lugged carbon frame, so it wouldn't even make sense to make a welded aluminum version.
Shop around and you'll find a Dream or Dream B-Stay for the same price as the opening bid on that one. Here's a copy of the 2008 catalog I found with a quick search.
http://beverlyconnellydesign.com/Bev...talogLoRes.pdf
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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