This isn't quite accurate. He says he got them at the Houston Livestock show. He doesn't say anything about who gave them to him. Then he says he lied to CBS about the source after CBS pressured him about chain of custody--told them it was a former Guardsman who was overseas now.
"While he had initially said he got them from another former guardsman, people at CBS said, he then told them that the documents came through a convoluted process that started with a phone call from a stranger and ended with the handoff of an envelope at the Houston Livestock Show, that city's version of Mardi Gras."
To be completely accurate, he got the phone call from a stranger and someone who he may or may not have known gave him the docs at a livestock show. Sounds more like an X-Files episode to me.