Do You Recognize This Pattern?

Not the woman, we know who the woman is -- it's C.'s aunt, and this was a prom gown she thinks was made by her grandmother in the 1960s. She's trying to figure out what pattern it was made from.

I'm pretty sure I've seen this pattern, too, but it's not like I can just reach into the giant toppling pile of paper that is my mind and pull out a post-it with "Simplicity XXXX!" written on it. Would that I could ...

If your mind is better-filed than mine, and you know what this pattern is (or can make a good guess) want to leave a comment?