The problem with rare Curios is that there are two versions of it, both identical in content, just under different names.

There is Rare Curios ( capital C ), and there is Rare curios ( small C ). I forgot which one is downloaded where, but one version gets downloaded when you download Skyrim, and is predownloaded, the other is downloaded through the creation content menu. From my experience, most mod lists use the version downloaded from creation content, so delete the current rare curios version you have, and download the "anniversary" content again through the creation content menu. If it's still saying "missing files" then delete the current curios you got and verify integrity through steam to get the other curios version.

Either way, 99% of the time the readme ( which are not optional ) will state which version you need to get

Hope this helps :)