I will say that the biggest indicator that Wheating was not doping was his reaction to his performance. Normally when someone is doping and has a performance like that they are not as shocked, surprised or as truly happy as Wheating is in his post race interview.
Also athletes who are doping are normally well established, part of doping circles, and typically win the races that they doped for largely in part of the confidence the drugs give them.
I think that Wheating will not run faster than this for a while but I think he has shown that he has potential to be a medal contender in the future.