Sounds good ...yeah, that's what I'd do if I were in your shoes.
If you haven't yet ordered them, my hunch ...and it's only a guess on my part, is that the reason the covers in the CB-15AK kit appear to be a different color is that the bases for those --for some reason-- are black and the CB11WAB has a white base. Therefore, the color of the cover appears lighter in the illustrations for the CB11WAB. I'm guessing that they use the same cover for both products as if you enlarge the pictures on the etrailer webpages, they have the same exact markings --"SAE P2PC 89 DOT
2" So again, it's just a guess on my part that they are the same. However, it's not that much more expensive to order them separately so it's not that big of a deal.