'67 Barracuda Grills

So upon taking my 1967 Barracuda grills apart from the chrome encasing in order to rechrome and repaint the assemblies separately; I've come to notice a difference between the two black grill pieces and I did not take notice of it until after I took them apart. One of the black pieces have a flat edge on one side while the other is curved. Why is this and which one is left and which is right? Also the curved piece is beveled/contoured. Which side of contour is toward the outside of the car? The beveled side or the flat side?

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