I got my grilles powder coated for durability.
I asked for satin black (completely unaware of the dunkelgrau business) and was slightly disappointed to see that the powder coating finish gave the grille a very slightly grey-ish appearance.
So on the basis of this discussion i'm happy to report that powder coated satin black is effectively dunkelgrau anyway !
Attached - some pics of my factory original boot (trunk) space with a random black plastic extrusion (a Suzuki tail light to be precise).
The untrained eye would never pic the difference.
But thanks to whoever pointed this issue out, as I will be obsessively checking this on every pagoda I see from now on