To add to the Difference discussion, there is a way to tell a “Factory Assembly’ line Original” Grille Shell and a “Factory Replacement.
The Black band ind the middle extends all the way to the Headlight bezzle, where the replacements stop at the turn signal opening.
I learned something new with the “Because it has the rivets” comment.
I figured out a long time ago that my grillE Surround was replaced some time early in its time. I always thought there was little details that “just didn’t fit” (like the front lower moulding being a “Black painted over Woodgrain” piece.