I do not think that the Spoiler things are on every model so can see them not being mentioned. When I fitted a Spoiler to my ND, I had to drill the rivets out of my oem spoilers to remove them first.
Cannot comment on NC1 but for the NC2; it’s an easy and straight fit, beside that if feels like a quality item (especialy if you consider the price tag…) but to be honnest: i’m not 100% pleased with the styling, i might remove it , not sure (maybe a bit to “tuning” to my taste…) .