Halston Heritage Grey evening dress

Smoke grey Halston Heritage maxi evening gown from viscose jersey with a cowl neck, long sleeves and fully lined skirt, the dress is new with tags, however it has a little bit of a darker grey area in the front, can't be seen when worn and is only mentioned for correctness.
I had my dry cleaner look at it, they said it looks like a water stain and would come out, but they would have to remove the tags, but advised me since it is barely visible to wait until it needs cleaning anyway.
Since I am not sure about the grey, the colour doesn't work for me as well as I thought, I decided to rather sell it on as new with tags and have put a very low price on it (I won't be taking offers). In case you have concerns, Look at the pictures, it is such a slight colour difference that not even the camera picks it up and can only be seen if you hold the dress under the window, due to the way the dress flows, when worn it totally disappears, I just want to be absolutely clear in my description.
The dress is super heavy and falls quite well, I have manually reinforced the stitching on the vent, just for more additional security (I have ripped a few vents in the past and found that putting a few manual stitches in avoids this)