For my 2 cents--like Sam said--NOS or good used is the way to go if you can find it, be it fenders, grille, or anything else. I'm learning the hard way on my '68. Oddly enough, I'm in the stage of
trial-fitting all the glass, weatherstrip and trim before I take it back apart to paint it, and I keep running into problems. The Goodmark header panel holes don't line up with the factory grille attaching holes, some holes on the doors don't line up with the weatherstrip Christmas trees and screws. I used aftermarket seals on the 1/4-windows and had to redrill the holes to attach the chrome pieces to the glass. The aftermarket lower windshield reveal molding doesn't quite match the factory holes....it goes on and on.
You have to understand, Jimmy, that most websites and even magazines don't have the time nor capacity---or I daresay if they're trying to sell something--the inclination, to reveal the warts as they go. They're professionals who think nothing of elongating a hole or tweaking a tailpan to make it work. It's their job to make it look easy, and it IS for them. To poor schmucks like me who plunk down hard-earned and saved long green for a $300 door, I expect that door to be precise. Sadly, that isn't always the case, as I've learned. My view on aftermarket parts now is try and find NOS or good GM. If I can't, I buy the best repro and HOPE it fits. I'm not knocking the aftermarket--very little NOS stuff is available from GM anymore and the aftermarket provides needed venues, but don't expect GM fit and quality on most of it. It's my opinion that aftermarket advertising turns their imperfect sow's ears into a lot of silk purses for the consumer to buy. My 2 cents for what it's worth after experiencing it firsthand. I'd always heard Goodmark was the best sheetmetal repro company going...I'd hate to see the worst.