It definitely is two parts, you can see the shadow of seam allowances under both edges of the bronzey/gold facing around the top of the dress bodice. The good thing is that the quirks of 3D animation make the layers act as one. So you can indeed get away with making them in two parts but joining them together. I'd recommend at the lower edge of the gold/bronze edging of the bodice. It won't be as obvious as at the top edge
You can easily then also cut away the excess under the body to reduce bulk or extra layers of added warmth.