.............. I didn't see anything about when the effort would be appropriate or needed.
Look at it the other way
Since the goal of restoring is putting the car back to the way it was originally built/delivered is there a time when its NOT appropriate to use the right parts
I always expect to see a representation of an original, correct for year, application and plant, when I view a car or consider it for purchase. Anything less IMHO speaks volumes (like other details) as to the efforts and knowledge of the owner and builder. Don't fall for the "No one will notice" line.
Remember the end product is a collection of your choices.
Your communicating to others when they view your work - make sure it communicates what you were trying to convey.