Oh, Hubbard wrote it, alright. Hubbard was a writer, and he could write stuff.
The editor of most of Hubbard's 1950s books, and the Editor of the old 'Ability' magazine, John Sanborn, recounted, in an interview of the mid 1980s, how Hubbard had joked about it with him. It was, privately, considered, by Hubbard, to be ridiculous.
That was around the time of Hubbard's activation of Scientology's "religion angle," as Hubbard called it.
In 1954, Hubbard had spoken publicly, respectfully, of Buddhism, and even of Taoism, and also of the Vedas.
He wanted to show that Scientology followed in the long tradition of these subjects, and even briefly spoke positively of Christianity. The 1954 'Creation of Human Ability' book opens with a quote from St. Luke of the Bible.
(As Dr. Winter - who had written the Introduction to the first edition of 'DMSMH' - had noted in 1951, when describing the disparity between Hubbard's noble sounding (essentially PR) proclamations and actuality, such things were "lip service.")
During 1955, Hubbard not only wrote his (meant for Scientologists' eyes only) "
ruin utterly" and "
always attack" '
Manual on Dissemination of Material'; he also wrote the fraudulent '
Russian Textbook on Psycho-politics' where he depicted Scientology as a target of the Russian Communists; and, also wrote the '
Hymn of Asia', where he depicted himself as the reincarnated Buddha.
By 1961, however, in a lecture (23 June 1961), Hubbard denounced Buddhism as a control mechanism devoted to keeping people quiet.
"
And of course, how quiet can you get? Dead. And you just might say, it's a covert effort to kill everybody off," Hubbard told the Scientologists.
However, there was a back and forth on this, as Hubbard, when emphasizing his "religion angle," would abruptly mellow on (wog) religions and become appropriately tolerant of them - when it suited his purposes.
Meanwhile, the 'Hymn of Asia' collected dust in a file cabinet or in a box somewhere, until, in the mid 1970s, it was revived and published.
These are 'Advance!' magazine covers from 1974:
I can be addressed
But in our temples best
Address me and you address
Lord Buddha.
Address Lord Buddha
And you then address
Metteyya.
L. Ron Hubbard, from 'Hymn of Asia'