I was at SeaWorld last Monday and visited the B&M fabrication factory on Friday morning. There's absolutely no steel on site at the Manta parcel, but I do believe that they have begun fabricating the first pieces after what I saw on Friday. The pieces I saw were pure white, but I believe that's the primer and not the actual coat that guests will see. (Dive Machine tracks were still on site, and Kings Island's tracks were in bundles ready to be shipped to the park).
There's still a bit of uncertainty on the color of the coaster, and I certainly hope these things get cleared up eventually by the park; but from what I've seen, the attraction is not only going to be bigger than I originally expected, but it's progressed so much in the last 3 months.