Unsure if vintage. Eyelet material is around the opening only. Going by the measurements, I'm assuming it is twin size.  Also, I haven't seen a duvet cover quite like this with the opening in the middle.  I really like it. It was sealed and I did open to take pictures. 

The Webschatz German Bed Cotton Duvet Cover is a luxurious addition to any bedroom. Made from 100% cotton in a solid white color with eyelet trim in opening, this duvet cover exudes a 1960s style with a touch of Noveau, Sweet, and Romantic themes. Measuring 78” in length and 61” in width, this Twin-sized duvet cover is perfect for adults looking to add a touch of elegance to their bedroom decor. Designed in Germany by Webschatz, this duvet cover is sure to bring a touch of sophistication to your space.

Pictures are part of my description.

Please check measurements and ask questions before you purchase.