I remember reading an article in the last few months about snake quilts - anyone remember it? It was in one of the quilting magazines. I'm going to see if I can find it for you. It was very interesting and might help you date this quilt.
Found it - it's in the June/July issue of Quilter's Newsletter. If you don't have the issue you can get it on their website at
www.quiltersnewsletter.com.