Chuck Schmidt wrote-
My '85 Bianchi Centenario (# 00.227) that I'm guessing must have been made very late '84 or very early '85 has the typical Columbus SLX tubing decal. Bianchi's 100th year in business was celebrated as a big deal at the time I remember.
I think that points out an interesting aspect of dating stuff, Significant builders got stuff first, often many months or longer prior to others, First short reach Campagnolo brake calipers I saw were on a DeRosa from 1974, it was a long time till I saw a second set, longer still till the domestic distributors carried them on a normal basis. The OEM buyers of bicycle components were not treated equally, obviously there was a pecking order.
Catalogs help, but often "new" stuff was vaporware or old news when a catalog was printed.