And send an email to CentroDocumentazione@alfaromeo.com and they'll respond with the build date, sale date, original color, and distributor originally sold to. Engine number does need more digits.
Do you mind sharing the Bertone number that is stamped in the body near the vin plate? On your car it is probably *6511xxx*. There are a few guys trying to crack the code between Bertone numbers and Alfa VIN numbers and every datapoint helps.