No if you watch the Go matches, AlphaGo did a lot of things that the professional commentator found odd, but they ended up working out. I expect if you saw similar odd tactics in the future you could guess you were playing an AI.
What does it mean that the commentator found odd? AlphaGo won, and the fact that the commentator didn't understand what it was doing doesn't mean there wasn't a purpose behind them.
You don't seem to be realizing that AlphaGo plays "oddly" like a chess grandmaster plays "oddly" against a new player. The "oddness" is that it's so good that we can barely understand its game.
You're creating a false dichotomy. AlphaGo plays both oddly (definition: "in a way that is different from what is usual or expected") and better.
The real point that I think hacker_9 missed is that AlphaGo was not trying to play like a human, it was trying to play better. If it tried to play like a human, it's quite likely that it would be indistinguishable.
In the latest matches, though, you'll find that some of the odd things that AlphaGo did ends up being adopted by the Go community. So are we now playing oddly, or did AlphaGo simply teach us?
Comparing chess and go AI to one another isn't a great comparison. As a high-level chess player, when a chess computer makes a recommendation to me, I can generally immediately recognize the reasoning behind the move, although I may need to investigate to understand why it's better than other options. Chess engines are recognizably different from human players in stylistic ways (no fear, etc) but the way in which a top tier engine like Stockfish plays chess "oddly" is very different from how AlphaGo plays go "oddly".
Stockfish views chess completely objectively, unlike a human, but ultimately plays in ways that a human can recognize immediately.
AlphaGo, apparently, does not.
This may change over time as human Go players learn from the AI.
