You might go to Louis's blog and search for the word "Nutmeg" to see if anyone asked that question at the time these items were posted. Or just to compare his photos.
I don't have the nutmeg in either piece but I see Louis mentioning things matching tonally and this could be the case. Doubt they would be an exact match because of how dyes take to different fabrics, but they could be close enough to work.
Regardless, if you like these autumn shades, give them a try. That WK skirt is not coming back (too bad because I like the longer length as a alternative). And if you have olives and other autumn shades that will work with these pieces already in your wardrobe you might get a lot of wear out of them as seperates.