That’s the thing...its not an EO. Just a redefinition of the term “manufacturer” by the State Department and their bureaucracy! It applies even if you only make one performance mod, or one gun part. AND export is irrelevant.
administrative diktats can be cancelled by a new administration too
And I think what the article says is “commercial gunsmiths” so my interpretation is that the hobbyist/owner isn’t someone covered by this in toto.