AWESOME find! I've been into vintage TV's for years and can confidently say that you have a set that's as rare as a pre-war. I too would see it as a "Holy Grail" set because not only is it rare, but it is one of the best art-deco designed '40's TV's of all-time. There was more than one version of this set. I believe there was another by Columbia, but this one is my favorite. Even the "Videodyne" name is so cool. I am envious!
Good luck with that gem!