Several years ago, I was fortunate to obtain this preproduction prototype from the son of a retired Zenith Engineer in Chicago. It is truly special because of how early it was made in the long legacy of the Royal 500, and because of the unique components used in it, some of which changed once Zenith went into full production. Check out the chassis photos and compare them to your handwired radios.
Upon careful examination, there are some things that you will find that are different from later handwired model. Of special note is the missing color paint dot that is usually on the install battery plate. Also of special note is the missing labels that are usually inside the back cover. The battery cover did have a sticker on the outside that read NOV 55 on it, but it has since come off.
This radio was well protected by it’s Zenith family, and believe it or not, it does still work. It would work even better with new capacitors, but I will keep this one all original as it is an important part of history in the development of the transistor radio in America.