Without getting into ROM editing, were these protos actually "Licensed by Nintendo"?  Does the license refer to the company or the game?  There are no known product codes and no content review, so my guess would be that they are not yet licensed games.  

I don't believe that Arcadia VI or Hoppin' Mad have that info, I'll have to check the ROMs when I get home to be sure.

I have 9 protos of a Gameboy boxing game, each at a different point in development.  I could go through each one and see when the info gets placed into the game if it wasn't included from the get go.  Each is dated, including the "Final Version", so if we compare it to the release date it may be helpful in determining when Nintendo would license a game.

I also have protos of released games with MAJOR differences that have the licensed info in them.  First that comes to mind is one of my Super Pitfall protos for the SNES.  Different temple name, different item names, password system totally missing from the final version, still "Licensed by Nintendo". 

It's simple. Publisher pays lots of money to get an official Nintendo license, any games released by that publisher is an officially licensed product.

Arcadia VI and Hoppin' Mad do not have that information because neither proto had a publisher attached, they were both demos being shopped around by their respective developers to publishers, hoping to get the project funded for completion.