Are you going to make or purchase a "Fake" tag?
Depending on the rarity of the model and the target market for the car, having the "Original" fender tag can affect the sale price / value of the car.
Just depends who is buying it and why.
That said, You "could" look for the Original Factory Build "Broadcast Sheet" (usually found under seats, under / behind the rear seats, etc, but it may have disappeared over time.
Finally, you could write down the Options / Standard Equipment items you have on the car, and Decode / Translate these into the Factory Code numbers.
Here is a fairly good Tag Decode List:
Tag Decode List