Assuming it is orignal, the Sprint rear derailleur would suggest 1986-1987. The 1986 Brava ($399 US) certainly was Sprint equipped though spec'd with Columbus Matrix tubing. I don't have the 1987 specs, but the Bianchi Formula tubeset is more indicative of a 1987 model, unless there was a running change during 1986. The serial numeral would appear to indicate a Taiwanese model of this period.