Even if you replace parts that are not original to the car, but are original to it's build, that will be so close nobody will ever know it didn't come with the car. Month of manufacture means nothing. It's the appearance that counts.
Almost every Pantera that is for sale is listed as "Original" but few are. It sounds like you're as close as you can be, but I'd want to see pictures of the entire car.
What about the interior?
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