To date, there are no official reports of anybody going missing and not being found or accounted for, in Sam Houston National Forrest, in the area or time period specified.
There are some people that would claim there is a "cover up" and that any reports of missing campers were deliberately kept silent by local and/or federal authorities. However, even if you subscribe to this theory, I can guarantee you that they could not keep family members from speaking out.
As a father, son, husband or friend, there is no legal authority that could keep me quiet if one of my loved ones did not come back from a camping trip. I suppose they could have me killed but that would lead to all sorts of other issues.
To summarize; no reports of missing campers, hikers or anybody else, in the time period and area where this incident allegedly took place. Furthermore, there has been no public outcry of anybody claiming to have lost a loved one in this area, that I could find.