The factory rear mud flaps do not fit the Nightshade editions. The front mud flaps fit fine.
I purchased these from Advance Auto Parts (pn: 4322). They come as a pair. They are almost an exact match in plastic texture to the factory mud flaps so it doesn't bother my OCD that much.
For the holes I simply matched the factory mud flap holes, marked, and drilled. No pics of that process.
I used the the hardware that came with the factory mud flaps to attach the mud flaps. No new holes have to be drilled. You will need a longer screw for the inner most hole location. I used a long bolt and nut instead.
I also cut small washers out of the factory mudflaps to put under each screw so that the mudflap wasn't rubbing the Nightshade bottom trim.
Final results. A good fit. The good thing about making your own holes is that you can position the mudflaps higher, lower, canted, etc. by just drilling new holes. My "cant" was off a little so I had to redrill new holes. I simply left the middle bolt in, pivoted the mudflap out and drilled new holes. You may be able to see the old holes in one of the pictures. If I'd have known it was this easy I would have skipped the factory mudflaps all together and use these for front and rear.