This letter brings up some very good points. And I can relate to it
because of the Masi restoration I undertook. For the record, all the
Campagnolo catalogs from (at least) # 15 thru to #18 contained the same
lineart/clipart while the iterations of each component evolved. For
instance, use an eagle-eye and notice that brake lever handles had a
different shape at their top, rendering them kinda' like 'long reach'
levers in their earliest production. This type bears similarity to all
others, but they're not the same. I suspect the production changed in
the early '70s, but the photo/art?? in the catalogs never did. There
are all the cpsc changes, the derailleurs with circlips, the logo
markings, and on, and on...
For a short period it drove me nuts as I, too, tried to use the catalogs
as a guideline for procuring the 'correct' pieces for my project. The
letter-writer is correct; the auto industry documented the parts used in
a way that (one-day-to -be) vintage bike makers could never have imagined.
It doesn't mean we shouldn't strive for exactness. If it takes over our
lives, that's a seperate issue. Otherwise, I'm for doing it as correctly
as possible as an homage to all the beautiful work that inspired us to
pursue this fascination in the first place.