Barra of Italy Mid-Century Dress

This gorgeous sleeveless dress was purchased in 1965 in Naples, Italy. It has a back zipper, no pockets, and buttons down the front. It appears to be missing one button. Measurements are of: bust, waist, hips, and overall length. There are some minor stains under the arms but not very noticeable. The size is 12 but I would size it at a small in current standards.