No. It's not.

I could create a raffle where I know what the result will be ahead of time.  I could tell the result to my friends so that we would win every round.  I could then hash the pre-determined result and "release the hash".  After play was over, I could release the result to prove by way of the hash that the result wasn't modified after the beginning of the game.  Unfortunately, this would not be a "fair" game.

Releasing the hash is only one part of a provably fair game.  It prevents the game operator from changing the result after the game begins, but it does not prevent the game operator from knowing the result before the beginning of the game and taking advantage of that result.  This is why Satoshi Dice uses a hashed secret combined with the transactionID.  Satoshi Dice cannot know the transactionID before the transaction is submittted, and the player cannot know the secret before the day is over.