I was just browsing NamUs for looking for missing girls in Virginia on something unrelated to this case, and stumbled across this girl:
Helen Allison:
By bringing people, information, forensic science and technology together, NamUs helps resolve cases.
www.namus.gov
Not much info on her, and there is a 2 1/2 year lag between DLC and discovery, but the resemblance to our Santa Fe JD is interesting. Her physical description - hair color, eye color, height, weight, strong chin, high upper lip. She would have had to have permed her hair, but alot of girls did that in 1974.