I believe the date is the actual date. Reviewing our label resource, as written by FuzzyLizzie, we see that Design Research closed in the mid 70s.
The label and skirt are both so pristine, that they appear as if they were only just made, even though the skirt is vintage.
"Marimekko is a Finnish company, founded in 1951 by Armi and Viljo Ratia. At the suggestion of designer Riitta Immonen, the Ratis's, who were manufacturing boldly printed fabric, began making dresses from the fabric. The first dresses were designed by Immonen.
Marimekko is famous for their brightly printed textiles – large abstracts and floral fabrics used for home décor and made into simple clothing and handbags. In 1954, their copyrighted logo was created. The company is still in business.
The second label is a Design Research label. Design Research was the American representative for Marimekko at the time. Design Research was based at Harvard University, and the head of the group was Benjamin Thompson, the head of Harvard's Department of Architecture. The group's original aim when it was formed in 1953 was to introduce better design into home furnishings. Clothing was added to their mission in 1963. Design Research closed in the mid 1970s."