The earliest ad for Holmes Basic?

The earliest ad for Holmes Basic? Found in the 1977 Gen Con X Souvenir Program, pics courtesy Demos Sachlas. Read more here:

http://zenopusarchives.blogspot.com/2018/12/1977-gen-con-x-souvenir-program.html
http://zenopusarchives.blogspot.com/2018/12/1977-gen-con-x-souvenir-program.html