That seems pretty early for Colnago. Did you get the date from the components?
http://www.vintage-trek.com/component_dates.htm
Here are the earliest references I could dig up:
http://www.bulgier.net/pics/bike/Cat...nago-88/19.jpg
http://www.bulgier.net/pics/bike/Cat...nago-88/20.jpg
Not much help, I know ...
I bet it's pretty!
Bob Hufford
Springfield, MO