It was in an article in the DM Register and I didn't believe it either. But he talked about being contacted on Twitter by them, and then getting a phone call from their RB coach, Tony Alford, who used to be an assistant at Iowa State. So it seems plausible, or else he flat made it up and lied about it to the Register.
Supposedly the OU wrestling scholly also comes with an opportunity to walk-on to the football team there as well. I don't think schools like Oklahoma and OSU treat football walk-ons as seriously as a school like Iowa might. You often see several players in the depth chart here who were once or are currently walk-ons. I seriously doubt that happens at the major football factories very often.
Still, it begs the question how a kid can get recruited walk-on spots from 3 of the Top 6 teams in the final Playoff rankings (before the bowls) and not manage to gather a single FBS scholarship offer in that sport. Strange.