Welcome to the forums. This this bicycle is from a market where they drive on the left hand side of the road, based on the light bracket on the right hand fork blade. Most members are American based and there's too much variation in Bianchi between markets to make any assumptions just because a dropout may be unfamiliar.
However, that rear derailleur appears to be a Shimano Positron II or Positron EM, which was available 1977-1982. Taking that into consideration with the steel cottered crankset, steel rims and stem shifters and we are talking a very low end bicycle that appears to be from the very early 1980s.