Well, no, I really doubt it. But, the dunk he did, when he threw it off the back of the backboard and then windmilled it in -- Rob Diggs did it a few years ago.
Who is Rob Diggs?
Exactly, that's why I don't actually think Dwight Howard stole the idea. But speculating sure is fun!
Oh, and to answer the question, Rob Diggs is a 6-8 forward on the George Washington basketball team. Here's video of his dunk.