So sorry for the confusion everybody! For saying that 3 of the CWs had black sky/cloud corners. Just ignore me.
I really do think the corner on CW 05 is black, but to be honest I can't recall 100 percent from my memory that it truly was. Forgive me!
However, something that I've noticed, though I may be wrong again—is that with the official colors, the first color listed seems to match up with the color of the sky in the upper right, cloud corner.
For example, "rouge" is the first color named for CW 03, and the sky on there is indeed red. "Marine" is first for CW 10, and
@ABQ2ATL was kind enough to correct me that it was indeed a navy/marine
"Turquoise" for CW 07, which matches up with the turquoise sky on that CW. And so on and so forth. I took this screenshot from the USA site by the way.
So given everything, I would go on to deduce that that there could be a good chance that the corner of CW 05 must indeed be black/"noir"??
I regret not taking more pictures