I picked up a representative example of what the OP wonders about this past summer.

1981 Specialissima. During this time period, the Bianchi Super Corsa and Super Leggera were the top two complete bikes in their range. Super Corsa was pretty much all Super Record and the Super Leggera was Nuovo Record. The Specialissima, from what I've deduced, was offered as a frame/fork only and didn't actually carry a name on the top tube like the other two did. However, the frame is identical in every way to both the SC and SL, using Columbus SL tubing and featuring the same paint/chrome finish.

When I purchased it, the bike was kitted out in with Super Record crankset, derailleurs and seatpost, a Cinelli bar and stem, Modolo Professional brakes, Phil Wood hubs and BB, and a pair of Vittoria Superlight pedals. Oh, and a Nuovo Record headset. You could call it a Frankenbike, for sure. I tweaked it over the months that followed and today it's almost completely Campy Super Record/SL with the exception of the headset - and I left the Phil BB in as well. I substituted a 3ttt bar/stem combo and swapped the crusty Brooks saddle that came with it for a 3ttt version as they were suppliers to Bianchi in the era from which this bike came.

As it stands today:



DD