I also have seen painted inside earlier housings Jeff, but the reason I stated it that way is because I have seen Perkins call it out that way(at least for small block cars) and made an assumption that it was the way MCA cars are judged since he is Head Authenticity Judge. Not really sure if thats how they are judged or not. And, I know that that could very well be differences between year-date-plant.
I like to add a little history when I post even if it does not directly pertain to the year-plant of the OPs questions because some newbie might come in and read something specific to year-date-plant and apply it over a wider spectrum and it can cause some confusion in instances like that. When I joined Concours Mustang it even took me a while to realize that a lot of you answer questions specifically to year-build date-plant and it would cause me some confusion. I know you like to do it that way to quell any misunderstandings but not everyone catches on to that right away and I know it took me a little bit to figure that out.