Directly from TMEA's Honor Band information website:
a. December 1 – rehearsal preparations for each program’s Honor Band submission may begin.
b. Examples of Honor Band rehearsal preparations include, but are not limited to:
i. prior performance,
iii. rhythm exercises,
iv. audition excerpts,
v. or sectionals that are directly in support of, or contain content within, the repertoire planned for the submission.
Handing out the music itself is all four of "prior performance," "rhythm exercises," "audition excerpts," and "sightreading." Just because it's not formal doesn't mean it's not extant. Plus, it falls under the "included but not limited to" clause.
The music should go out December 1, and not before.