[Chuck Schwark]

Actually, that would be called a Code 124 chassis version.
Model numbers would go through minor and major production changes.

Minor ones would be documented as "Production Change Notes."
Major ones like tube type changes, parts changes/deletions that made
significant schematic differences or some mechanical variation were called
CODE versions. All models started out as the base model, Code 121.
Usually, base models did not actually have Code 121 on the labels, although
some did. No consistancy. Philco used Codes 122, 123,....up through 130,
depending on the model.

:-)

Chuck