I've attached a link from Mark Bulgier's list of catalog scans for a 1983 Bianchi catalog.
Top of the line was the Super Leggera for 1983. It had been the Super Corsa, which was dropped by '83. I believe that the Specialissima, at least in 1983, was just a frameset.
The Super Leggera was basically a built up Specialissima frameset.
The Reparto Corsa framesets, to my knowledge, all had the chromed Bianchi caps, not the circle B's. Also, chromed drop outs, chromed fork crowns (painted tops), and chromed chain stay. The earlier Super Corsa and Super Leggera's had chromed head lugs. By '83 the RC framesets no longer had the chromed head lugs.
Also, the Reparto Corsa frames typically had a gold foil decal at the base of the seat tube with the month and year of manufacture. Also, the top tube brake cable braze-ons are very thin, not typical of the era.
Jeff Pyzyk
Milwaukee, WI