One problem I see with applying 310.120 "Marking" as a standalone article is that it states "All Conductors and Cables". Cable assemblies are made up of conductors, so the way it reads you would also have to include equipment conductors, since there is no exception or reference back to other articles that allow for equipment grounding conductors to be bare, covered or insulated. AFAIK, only insulated conductors are marked, so technically bare and covered equipment grounding conductors wouldn't be allowed to be used anywhere, not even in raceways or cable assemblies, but I've never heard of any inspector applying the article that way.