Paint daub’s/inspection mark’s

That's true.
I'm sure every guy working on an assembly line had their own style of how they marked things.
I would search around on line and get some examples, then mark it to what you see fit.
I don't think anyone is going to question it, as long as you have the basic areas and colors covered.
Heres an Interesting article on markings (B body of course).
Gallery: '66-'70 B-Body 8.75 Rear Differential Identifiers & Markings - Mopar Connection Magazine | A comprehensive daily resource for Mopar enthusiast news, features and the latest Mopar tech