Simplicity 3538 vintage sewing pattern, dated circa 1960. 

Misses' One-Piece Dress with Two Skirts:

Dress has round neckline, kimono sleeves, back zipper and lowered waistline with bow trim. Top-stitching is optional. V. 1 features slim skirt with soft pleats at upper edge and just above-the-elbow length sleeves. V. 2 skirt has double inverted pleats and sleeves are shorter than V. 1. 

Size 12:

Bust 32 inches / 81 cm
Waist 25 inches / 64 cm
Hip 34 inches / 86 cm

Pattern is UNPRINTED, checked complete. Envelope has wear and tear, spotting.

More '60s patterns here:

http://allthepreciousthings.com/collections/1960s