Daily Mail Australia has also uncovered the Intellectual Property registry of her 2002 play The Westie Monologues - which was lodged by a Melanie Elizabeth Bownds.
Wilson addressed the claims with a series of quips on Twitter, calling it "tall poppy syndrome".
The strange situation could be explained by a 2011 quote from Wilson, where she told The Herald Sun: "At school we went under our middle names usually. I have two - Melanie Elizabeth - so I was never under Rebel."
Further complicating the matter is that the Pitch Perfect star's great aunt was Walt Disney's wife Lillian Bounds, a maiden name very similar to Wilson's alleged name of Bownds.
The funnywoman's siblings are famously named Liberty and Anarchy, for her sisters, and her brother is named Ryot.
Rebel has joked to the likes of Ellen DeGeneres and David Letterman that she grew up in "the ghetto," Sydney's west, but her former classmate says she had a "upper-middle-class upbringing".
Tara Anglican School for Girls, which indeed is in Sydney's West is one of Sydney's top schools and currently costs parents tuition fees of up to $25,000 per year.
"I'm from Sydney, the western suburbs which is kind of like the real ghetto area," Rebel told David Letterman last December.
She added that her parents named her Rebel because "a little girl called Rebel sang at my parents' wedding, and that's where they got the name from".
Meanwhile, in 2013 she appeared on Ellen and revealed her parents were "professional dog showers".
This is corroborated by a picture of Rebel presenting dogs with her mum at an early age.
However, the former classmate noted she never saw any dogs around at the future comedy starlets home.
Wilson has famously told of her rise to fame, which began when she contracted malaria in Zimbabwe as a Youth Ambassador for Australia.
Read more: Rebel Wilson: I wasn't allowed to lose weight
"I had this hallucination that I was an actress and that I was really good and that I went to the Academy Awards and won an Oscar," she told Maude Apatow in 2012. "That's gonna be my destiny."
The blonde's breakthrough Hollywood role came in 2011's Bridesmaids - a role she secured after spending years accruing acting credits in Australia.
Wilson's been spending the last few weeks blazing a promotional trail for the sequel Pitch Perfect 2 - which has already grossed more than $100 million at the worldwide box office.
- Daily Mail