Original GM or Repro Doors Question

[72malibu]

I'm looking at doors.

I've seen a pair of 73-76 where the front edge of the door is not folded over flat, but instead is 90 degrees, beginning about halfway down the door. It's like that all the way to the bottom. And only the front edge, on both doors. I'm told they are original, but I'm not sure. They look like they would be GM replacements or repros, because they are black coated.

I have a pair of 77-up repros where the edges are completely folded over.

And I have a definite original 73-76 (red oxide primer inside) that is folded over. But that door has had a lot of bad body work done to it.

Can you tell if a door is GM (factory line or replacement) or repro based on whether the flange is folded over?

Here's a pic of a new AMD Repro