Esteban:
I believe that both are correct, because Udet had more than one Fokker D.VII.

There is an excellent article, "The Importance of Being Ernie's," (love the title!) in volume 3 (I believe) of the Albatros Publications Fokker D.VII Anthology, which discusses the schemes of Udet's various D.VIIs. I am in the office and the book is at home, so I can't give you all of the aircraft number details, just the basics from memory. There is a photo of Udet standing behind an OAW-built D.VII which has the candy stripe top wing just like on this model. I believe this aircraft was very short-lived, as it crashed after only a week or two of Udet's use. Thereafter, he used other D.VIIs, including the D.VIIF for which WNW offers the paint scheme with the red fuselage and lozenge top wing.
The larger controversy has been the color of the stripes on the OAW D.VII's top wing. Some saw black, some say red. That's really a matter of personal preference. I like the red, just like Petrov modeled it!

My preference is partly childhood nostalgia, since the cover art on my paperback copy of Udet's biography, "Ace of the Iron Cross," from around 1968, showed his D.VII with red stripes. I have always liked that scheme.

Regards,
Bob