Very interesting. It has Bianchi decals on the down tube and fork, most likely legitimate. It's only got braze on guides along the top tube and evidence of clamp on down tube shifters, water bottle bosses, and a bracket on the headset top nut for a double pull front brake, most likely older than '80. Campagnolo seat post bolts were common back in the '70s on other than Bianchi. They never broke.
The lugs aren't cut out except on the top tube which leads one to believe it was a lesser priced model, showing a bit of pretension, together with those fast back seat stays. The BB lugs are more substantial and look machine brazed. If the tubing emits a lower pitched ding, it's probably straight gauge tubing, not butted thinner in the middle.
i'd guess it's indeed a Bianchi but of lesser recreational grade than their top level racing bikes. The decals are from the'70s. Evidence of clamp-on shifters and water bottle cages date before welders trusted brazed on bosses not to heat up the thin tubes and make them brittle. The top tube brazed on cable guides started in the late'70s-early '80s.