Let's do this chronologically. It is not in the following
Hash House Harrier songbooks:

Inter-Hash Songbook, 1986, printed book. [Cover title Hash Music 1986]
Jakarta HHH 1994 songbook, printed book.
The Definitive Hash Songbook, (January 1994), by ZiPpY, printed book.
The Definitive Hash Songbook, (November 1994), by ZiPpY, printed book.
Hash Song Book, 1995, by Mu-Sick. (photocopy of typewriting).
[untitled text file], ca 2001, by Stray Dog.

And as reported above, it is not in the Flying Booger hymnal until 2001.

Anyone have earlier date (1970s, 1980s, 1990s) for the "Head? Who said Head?" repeated chant?