The pictures Merrique posted are the 1908 dresses. There are very different stylings between the 1908 and the Tercentenary dresses. The one that I notice right off is the belt/sash with the 1908. In the pictures of Olga and Tatiana, there is no belt there, instead, it's very fitted and one can tell that the wearer is wearing a corset. The second is the trim of the 1908... it's much more apparent because it was done in a different color than the dress, as where the Tercentenary dresses' trim is the same color as the actual dress (cream), with only slight pink details.
Anyway, it's a shame about the kokoshniks' state of repair. It would be great if they could restore them for when the dresses go on display.