I'd contact the Gatesville Public Library, www.ci.gatesville.tx.us/
and ask if they those records.
I also did a Google search for Gatesville Texas School for Boys and several web sites "popped up".
The Texas Department of Corrections may have the records. There were other web sites and a Facebook page where people who had spent time there posted comments.
Also they have/had a cemetery; State Juvenile Training School Cemetery which is on www.findagrave.com/
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