SIZE S? MARIMEKKO IS Sleeveless dress with pockets. E10

Marimekko Sleeveless Gray and black print dress.I believe it's a size small but there is no size tag or materials tag feels like cotton fabric.The dress is very well made and has pockets. The dress is shown on a size 6 mannequin But I'm guessing it's a small. The fabric does not have any stretch to it. The measurements are on a card in photos. The dresses in excellent used condition.