No, the only time she attempted the 3S was in the 2008-2009 season on the Grand Prix, and it was gone by 2009 4CCs and 2009 Worlds. It was otherwise omitted during that quad, 2006-2010, and she brought it back for the 2010-2011 season.
Mao didn't attempt the salchow much (if any?) as a junior, either, and in 2005-2006, Mao did not have a 3T in her jump layout, so yes, it is true that there was a time when Mao had neither a 3T nor a 3S in her jump layout (but had the 3A and 3F/3Lo).
Interestingly enough, had Mao perfected the 2A/3T back then, she probably would've won 2007 Worlds--her 2A/3T was downgraded in the FS and it cost her the gold.