Casting dates vs. build dates

[Mr70]

From what I've seen,the distributor was installed on the engine early on before it was deemed a self reliant running unit & reached the vehicle.It's date would've been anytime prior,(usually weeks before),to the engines stamped completed assembly date.

The carburetor was installed after that date,so it's date was more prior to the vehicles cowl tag started assembly date,weeks to a few months in general.

Understand these were just components sitting on a shelf,waiting for installation somewhere so some examples may differ from above.