It sounds so familiar! I am wondering if it was a kit from Herrschner's. It was a mail order catalog for crafts. The had a lot of kits. I loved getting their magazines. Also there are Aunt Martha's iron-on embroidery patterns. I used to love to go to Woolworth's and look thru the patterns. I started embroidering in 1962 when I was 8 years old.
If you find it, please post it. I am looking forward to seeing the quilt your grandmother made.