Just checked out the the beginning of the documentary
Directed by John Ford (1971) Peter Bogdanovich
Duke actually states on camera, that it was on the set
of Mother Machree, (1928)
when Ford got him herding the geese,
that it was this movie where he was 'kicked'
and that it was THIS movie that was his FIRST job with Mr Ford
Duke states:
QuoteSo when Mr. Ford needed a goose herder for his set,
it just fit my pistol. They had a hill made up, a fake hill for this
set of Mother Machree and the geese, were getting down under
the two by fours there, and they needed a fella to herd them out.
so that was my first job with Mr Ford
Duke went on to say
QuoteSo you're a footballer player said Mr Ford, get down
on my forearms and feet, and just kicked my arms from under me,
and stuck my nose in the mud that they'd made for Mother Machree,
and the rest is history.
As production started in September 1926
this would fit with all the information from the books.
I for one cannot dispute or argue with what Duke actually said!!