Well Dawid, really you are a bike dealer so you are obliged to know before posting the ad!!
Here is my Colnago Sport I used to own; notice 3 cable guides , ( it also had heart cutouts) , also note factory engraved parts and nice original factory paint and perfect Gipiemme groupset, plus the manner in which the seat stays are resolved into the seat lug... very different from the bike you posted.
Here is a link to another Sport with the same details as mine...http://img.photobucket.com/albums/v101/ ... C_3240.jpg
the sport was a lower end model so wouldn't have had chromed rear triangle I suspect.
Apart from the decals and the colour I can't see anything that would suggest it was genuine.
Colnago Super, C record Delta 7v,
Olagnero Signature Model, DA 7401
Battaglin EL101 tubing 8v
Wilier Campagnolo 8v Record
Daccordi Furioso, Campag Veloce 9v