Are there any other versions/variations to the flat hood?

Does anyone know when the changeover between flat hood versions happened? (guessing it would follow along with the shaker hood versions as the shaker was based on the flat hood)

What dictated the use or lack of use of the "DODGE" letters?

Were the holes for the "DODGE" letters pre-drilled? If not, the Fourth Version would be the same as the Third Version.

Input Please.
Tav