Rodney's Sauce
Rodney Scott's World of BBQ
While I was not surprised to find an eastern North Carolina style BBQ sauce recipe in a book from a restaurant in South Carolina (most restaurants even here in ENC have several styles of sauce for different meats and to suit different palates), but I was surprised that this is just, well, Rodney's Sauce. There are other sauces that are mote commonly known as South Carolina style, but this isn't it. Not that I'm complaining!
I do recommend that you make this sauce in advance. When I tasted it right after making it, it seemed like it would be VERY spicy, from the cayenne and red pepper flakes. That day I used it in a different recipe (coming soon!) that included much more sugar, so it wasn't as much of an issue as it would be on meat. By the time I tried it on smoked pork, though, it had mellowed considerably. (Don't worry, this will keep an absurdly long time in the fridge, being mostly vinegar.
I found two scaled-down versions of this recipe online, both a bit different. This one is more true to the one in the book: https://destination-bbq.com/rodney-scotts-bbq-sauce-recipe/ And this one is a bit different, but similar enough that I suspect is is as good, if not a bit better (I do love ancho chile powder): https://www.allrecipes.com/recipe/8416149/rodney-scotts-secret-eastern-carolina-barbecue-sauce/