When vintage dresses are placed in specific decades in the shop, it's sometimes based on what decade the dress is better associated with. Some dresses, especially when they fall in those blurry years (right at the end or start of a new decade), are just too hard to pinpoint an exact decade, so while a dress may appear from the 50s, it could actually be from the early 60s.
Don't you wish dresses required a time stamp? LOL!
Picture credits: 1.] Sugarpie Honeybunch, 2.] Rick Raven, 3.] same source, 4.] Astro Girl, 5.] My Sweetie Pie Pie, 6.] 1961 Vintage Dress Pattern from McCalls, 7.] 1960 vintage dress pattern, 8.] Family Circle, Summer 1960 Jackieinmi