[Mr70]

Flint & Tona added the starter motor after the engine was fired up & stamped with a build date & suffix code in the engine test room and headed for a deemed vehicle.
...But that doesn't necessarily mean the starter motor <span style="text-decoration: underline">has</span> to be dated after an engines running assembly date,as the starter motors were pre-ordered ahead of time and waiting to be added on,when various other dated components were added later on.

I think your fine with what you have found,as the vehicles cowl tag assembly date is what you don't want to really be after.
And although uncommon,it's not impossible to find an original unmolested engine,still holding it's original unmolested starter motor,dated before the engines running assembly date.