It's a separate bodice and skirt. The skirt is linen. The grommets are light gold (I made that mistake with mine, because the DVDs weren't out yet so I missed all of this wonderful info.) The inconsistencies with the color is definitely the lighting and filters they use, but probably go with the shade from outside since that's more natural lighting. If you notice, she is laced into the bodice differently in the dungeon scene and I think it's because they all get two of the same costume...one for stunts and one for close-ups and non-stunts. If that's the version she wore to get thrown into the dungeon, it might be the "stunt" costume and someone accidentally laced it differently. I did mine like it was for the rest of the episode, with the laces forming an "x" shape.
Hope that helps!