There was speculation that the corner pieces were shaped sliiiightly differently compared to pre-facelift, but I don't know if that was ever confirmed. Otherwise, as Speedy mentioned, the center ducktail piece needs to be notched to for the facelift handle.
The 'blended' ones used composite ducktails with filler to blend, AFAIK. Never seen or even heard of a metal ducktail sold separately, which if it exists, would be aftermarket / non-AMG.