I suppose that since all 4 of these Remnants are "Salvage" zones, and thinking upon the idea that the beastmen are running around in there too, and the fact that the Pliniths are "detachable", it would make sense that Al Zahbi took the Silver Seas Plinith,
whereas the other three Pliniths were taken by each of the beastmen forces surrounding Al Zahbi.
I've never been inside the Hall of Binding after the AC was stolen, but don't the beastmen remove the whole plinth along with the candescence? I never bothered to compare the crest on the plinth in Mamook since I figured it was the same thing as in Al Zahbi...
Here's a screenshot of one, but it's kind of unclear which part of the crest is glowing the brightest. It loooooks like the top-right part, but that could just be the timing. Does anyone have a better shot of a captured AC?
http://i53.photobucket.com/albums/g6...s/img_0013.png