Originally Posted by T-Mar

Italian models having serial numbers on the seat lug only occurred during the Piaggio era of the early 1980s. In the late 1980s, the Italian models started using the bottom bracket shell. Your bicycle definitely has an Italian manufactured frame. I'm assuming that the '1' is actually am 'I', which would make it a 1989-1987 or 1989-1990 model. Typically, it would be the former but we've seen cases where careless Bianchi employees have reversed the sequence.

Bianchi S/N did not include model indicators. To determine the model and which of the two scenarios fits best, we'll need more information and preferably pictures. Start with a list of the components and a description of the Bianchi logo style.