How to find an old (1970's) women's sewing pattern?

My sister’s birthday is coming up, and I would love to find a pattern for an outfit that she made in high school that she has been looking for for several years. I can remember when she made the outfit, and what it looks like. (She lent it to a friend, who lent it to a friend, and it never came back.)

She made it between 1971 and 1975, because she was in high school. The outfit was featured in a magazine, either Seventeen, Ladies Home Journal, or one of those women’s magazines. She thinks the outfit was featured in an article about Susan Ford, Gerald Ford’s daughter. She made the outfit exactly as it appeared.

Description: Black and white gingham skirt and matching top. The skirt had a border of cross-stitched hot pink and red roses around the bottom. The top was sleeveless, and had a turtle neck collar and zipped up the back. The sleeve was cut in to the shoulder, looking like a halter top. It took her forever to embroider the skirt, but when she finished the outfit, it looked exactly like the one in the magazine. It was pretty amazing.