It's hard to argue a point that is very subjective with someone who may not be entirely educated in the process back then. Looking back at that time it was dependant on the person applying the paint to how far they wanted to go with coverage. Besides the bypass hose that was on the block when painted, the exhaust manifolds and bell housings (manual cars) and distributor clamp coverage were entirely up to the painter.
I have my entire bypass hose painted and never got docked points when I showed my car many years ago. I had a discussion with a person just last week about the Camaro build process and I told him the early Camaros' front end sheet metal was painted by Chevy and the main body by Fisher. He still doesn't believe me that was how it was done
Seeing the archice picture I may print that out just in case I encounter that situation like yours.