"Mexico cranks etc were definitely not an official Campagnolo deal... Campagnolo officially frowned on these customized parts as the carving away of components reduced the reliability of these items..."
If we are calling the highly milled and rounded cranks seen on Olmo, Colnago and a few others "Mexico" (never saw those words on them in the day) I can say with certainty that they were in fact modified by Campagnolo. I had always wondered about this and when visiting Campy on business in the mid 80's I had the opportunity to ask them directly. It turns out that for a few special and influential Italian builders, there were modifying cranks, shifters, brakes and seat posts. They specifically mentioned the Olmo, DeRosa & Colnago. There may have been others, but the brain cells are rusty now. Dale is right about Campy frowning on people modifying their products, but apparently that does not extend to their own work for Italian builders.
Bryant Bainbridge Portland Orygun where it is dumping buckets