That is probably the TOTL Zenith HiFi that year.
Most Zeniths covered in my 59-66 service manuals (books Im very happy to have
) , including two consoles I have, are single-ended 6BQ5. I can only imagine how great that will sound when restored.
The horns and the reverb amp alone make that special model. drh4683 might have a video on such a console