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No. Gary Sinise has done over 100 USO tours.
According to an article at USO.org dated April 18, 2017,
Gary Sinise & Lt. Dan Band Performance Marks Actor's 97th USO Tour
A later article,just last month(Mar 27, 2019), also at USO, says
Today, Sinise will perform his 100th USO Tour in Virginia Beach, Virginia, and weβd like to salute his service to our military community.
Since the Questioner stated in the body of the question,
Is there any documentation indicating anyone else having completed more than 57 USO tours,
...originally I was looking for some unsung hero who may have toured (headlined or not) more than 57 times.
the Gary Sinise information seems to qualify for at least that part of the question.