Misses' 1960s Vintage Jiffy One-Piece Dress Sewing Pattern: Slim dress with high round neckline and back zipper has extended shoulder line and optional self tie belt. V.1 and 2 have a tie collar. V.1 has long set-in sleeves and V.2 and 3 are sleeveless.
Simplicity 6437 Copyright 1966
Pattern is cut and in good condition, one piece has a bit of tape. The envelope is in good shape (image from sold pattern but similar shape).