Average Cost For Rear Quarter Replacement

If your body guy feels confident he can work it out, so that only a minor skim coat would be necessary, it would be crazy to replace it with an aftermarket part.
I myself have gone through extreme measures to save original panels.
Keep in mind that this is a unibody car that has gone through a half century of heating, cooling and stress cycles as one piece.
You have a better than 50/50 chance of there being some sort of organ rejection within a relatively short time