From the seller:
A sweet 1880’s white cotton bodice and bustle over skirt. The bodice is trimmed with brown braiding. The front is decorated with three bows that are outlined with brown braiding. The bodice is unlined and has a front hook and loop closure. The bustle overskirt is also trimmed with brown braiding on the edge of the hemline. The over skirt is unlined. Both garments are in excellent and sturdy condition. There are no holes and no age spots. There is a small area of loose braiding on the back of the skirt that will need minor re-stitching and wear to the braiding in this same area. Bust 32 Waist 26.
I have no idea why the seller thinks this is 1880's. The bodice and sleeve shape are still very 1860's.
|1870 Fashion Plate via the Bartos Collection|
The above is from 1870 and it's not hard to see the similarities in the extant dress and the white and black ensemble. For that reason, I'm putting this in the 1860's. (Remember, there is no year 0. Decades go from 1-10.)