Rare Jeanne Englehart pinstripe FLAX dress

This is a beautifully tailored long dress. VERY flattering on. Also rare -- it's a rayon\lycra blend = beautiful material. SIZE medium but runs a bit large as do most FLAX pieces. The dress is in pristine condition. I think I wore it 3-4 times. However, there is a very tiny black spot on back (see picture). I have not tried to wash/remove the spot, so I'm sure a dry cleaner could do so.