Well, I did noticed that for some time after 1931 the WTS used the phrase "Jehovah's witnesses" and the a separate group, companions, men of goodwill.
The Jonadabs were not invited to the memorial until 1938, 3 years after the GM change.
*** w51 5/1 p. 284
Planning Now for the Time to Come ***
The great amount of money that
is required in this period to carry on the activities of the Watch Tower Bible
and Tract Society and Jehovah’s witnesses whom it serves comes to us without
solicitation, voluntarily from Jehovah’s witnesses themselves, from their
associates, companions, persons of good will, and others who want to see the
Word of God spread among the people and desire to use some of their material
blessings to that end.