That's quite likely, actually, given the lack of transparency in Chinese internal politics and the lack of access of independent journalists to the relevant data.
Those last two are the most closely related to the massive property bubble in China and are also the reason the stock market is so volatile: companies own land and they own each other and that dynamic leads to a virtuous cycle of increasing market capitalization in good times, and collapsing valuations when valuations fall. Small price changes can have a disproportionate effect on market capitalization.
My business teaches Chinese online (http://popupchinese.com) from Beijing, so we're face to face with the economic reality here. And while everyone knows there's a bubble in real estate (it's on television every night), when you adjust Chinese GDP to account for purchasing power parity and adjust to the wage scale, the Chinese economy looks much, much bigger and more important than it seems if you're looking from an American perspective. Anyone who hasn't had the chance to visit yet definitely should! And start learning Chinese too.
Incidentally, a number of studies on Chinese energy use have cast doubts on its rate of growth for years. Still doesn't mean that the Chinese economic miracle isn't the story of the century.
PS: For comparison look at South Korea even though it's slowed down from 1995 to now it still grew ~300x from 1965-now compared to China's ~70x growth over the same period.
"According to our own proprietary Chinese GDP indicator, in December Chinese growth could have been 13 percent."