I've measured a lot of bottom brackets, and everything I've seen is in line with the ISO taper appearing on Campagnolo cartridge-style bottom brackets.

I've never measured a cup/cone campag spindle having ISO dimensions.

Sugino Mighty (and Suntour Superbe and Sprint) were also identically ISO dimensioned, for whatever reason.

A good way to compare tapers in isolation is to set a caliper to 13mm and ten see how far past the end of the spindle that the jaws can slide.
This eliminates the need for accuracy (as when taking actual measurements of the width of the spindle at some fixed location relative to the end of the spindle as shown below).