Ahhh...
This is a pre ExaDrive cassette, which dates it to between 1989 and 1993.
In 1994, Campagnolo changed the spline pattern so that the cogs could only sit in one orientation on the freehub body. This made assembly much simpler.
With the pre-Exa drive cassette, it is possible to slide the cogs on in ANY orientation, so you are in trouble unless you have the booklet that shows how to align the different cogs. The alignment depends on the size of the adjacent cogs.
I will look for the booklet, and if I find one, I'll post a scan up here.
Incedentally, the "A" "B" and "C" cogs you refer to, are not related to the orientation of the cogs. An "A" cog is defined as one that belongs next to the lockring in position #1. In a similar fashion, a "C" cog is the one that always sits closest to the spokes in position #8. The rest are in the middle and are "B" cogs. A pre-ExaDrive cassette should have one "A", six "B" and one "C" cog. The A should always be the smallest, and the "C" should always be the largest. I have seen shonky Ebay sellers mixing and matching As, Bs and Cs all over the place. Shifting would be ugly with those frankencassettes...