NO the Sandaime Kazegage's ability was not a Kekkei Genkai. His technique was very similar to the Shodai Hokage's in that it was a technique only he could perform it was not a Kekkei Genkai because like the Sharingan or Byakugan they would be passed on to their children and Tsunade does not posses the first abilities. This is one of the many things in Naruto that has never been explained.

For all you people who think that Gaara can no longer be the Kazekage I beg you to use whatever brains you have left. If he no longer had his abilities then everything Chiyo did and said about how Gaara as the Kazekage and Naruto as the future Hokage would change the relationship between the Leaf and the Sand and the ninja world as whole would be meaningless. I mean why give your life to save his if he doesn't have any of his abilities and can no longer control the sand or be the Kazekage it just makes no sense.

So whether you think its possible or even probable doesn't make a difference I can " Guaran Damn Tee " that Gaara is still the Kazekage and still has his abilities because if he doesn't Konoha trying to save him, Chiyo giving her life the save him, and all of Sunagakure coming to rescue him, the entire arc would be for nothing something i could see happening in Bleach but not in Naruto.