Vintage Jessica Mcclintock Gunne Sax strapless blue and black polka prom dress

This vintage Jessica McClintock formal dress is in absolutely perfect condition. As far as I can tell it has never been worn. It it's a 5/6. The dress is satiny black with blue polka, trimmed in sky blue, with a black crinlin lining . It is hand washable. I have already cleaned the dress. My mannequin was a little too large for the dress so I was unable to zip it all the way up in the photo. The zipper does zip to the top.