Not according to her bio at IMDB. She has never denied getting implants and she has even joked about it. Here are a couple of quotes from her on the topic:
(On the topic of her bust size) "People always ask me if they're mine. Yes, they are...all bought and paid for."
(Alluding to her famous bust) "If I build another park, it will probably be in Silicon Valley."
Maybe she's just joking to keep everyone guessing, but I doubt it.
I dunno, I always thought they were real.
There's only one way to find out....