Giordana (mainly associated with clothing) was the house brand of Gita Importing, they handled Pinarello among other brands, but the frames were:
"Some of the original Giordanas were designed and built by Dario Pegoretti and the bulk of the production were picked up by Billato. Do a search over at the Serotta forum for more details." a quote from this thread:
http://www.bikeforums.net/archive/in.../t-360863.html
Given it's a Cromor tubed model I'd say very likely made by Billato, which ain't bad.