It depends how you define fluke.
There is a "totally out of nowhere" kind of fluke, for things that nobody could have even imagined happening. Imagine if Vincent Ciattei had pipped Kessler at the Trials, made the team, barely made the final, and then won Olympic gold. That would have been a true fluke.
On the other hand, there are "If you run the race 10 times, it is unlikely to happen again, but it could," kind of fluke. That is what we are talking about here:
Centro was a global championship medalist from before Rio and as such had to be on your radar. He was one of the best finishers in the sport and everyone knew that. Not a "fluke."
Hocker was 6th at the last Olympics, as a 20 year old, and as such, was a "contender" by any normal definition of the word. You can't be a "fluke" if you are already in the top 5 in the world going into race.
That said, if Jakob hadn't drifted out into the outside of the lane (trying to run Kerr into lane two), Hocker would have had to go around on the outside. In that scenario, he doesn't get the gold. So seeing lane one open up with 100m to go is a bit flukey.
And in a normal world, they don't let Centro dictate the entire race and pace in Rio. That was just weird. But at that time, everyone liked the sit-and-kick style racing, so maybe that was fine for all of them. They all thought they had the best kick. That wouldn't change if you re-run the race.
Cole is the bigger fluke. (But not a fluke at all, actually.)