Another instance where some more information upfront may well have altered advice and possibly produced a better outcome.
using the Campagnolo tool to just remove paint is ok but quite possibly will end up removing too much metal where it was previously set up for a Campagnolo headset. Some razor blade or judicious emery cloth scraping or better yet, masking at the respray, a much more metal safe method.
the Passa/ no passa gauge is really for use on an unknown steerer, or frame set with questionable prep to begin with.
there was no reference if the size gauge was before or after facing. Having the tools is only part of the solution.
A reference - a “coin” era Gios, the frame headtube was not showing any reaming, the fork had a split Super Record crown race -
it was never dressed. That was remedied, I guess the softness of the Super Record parts allowed the forced assembly. Not every shop had the correct tools nor awareness.