The wrapped armored cable is actually wrapped around the wires and it is part of the wiring harness. In 1929 and in early 1930 the wrapped cable was used on the headlight wires for example. Also, this same type of wrapped cable was used on the accessory Sportlight wire as well.
The flexible armored cable is more like a flexible conduit and the wires slide through it since this cable has a much larger I.D. This type of cable was used on the tail light wires for example, and on the headlight wires in mid-1930 and later.
There were two types of rubber grommets used on the radiator shell in 1930 depending upon if the headlight wires were wrapped in the armored cable or if the flexible cable was used. As a rule of thumb, the change was made sometime around April of 1930.

:) :grin: