Welcome to the forum Matthew and congratulations on preserving this uncommon set. I see yours is mahogany, as is the one that I have. I understand that the other known one is blonde. It is fantastic that the CRT in yours seems to be good. I agree with the other responders that the testing issue is probably with the tester.
You mentioned 1958 but it is actually a 1956 set. There was a write up on it in the January, 1956 issue of Service Magazine beginning on page 13. The magazine is available here:
https://worldradiohistory.com/Archiv...ce-1956-01.pdf
Thanks for posting your find and please keep us abreast of your progress and feel free to ask any questions. Although my set has a good CRT, it is presently unrestored.