X5 E53 roof rust.. not painted from the factory?

[shedtastic]

So today I decided to fit the Kuat Vagabond roof rack (that I randomly swapped something for on Facebook market place, about a year ago) to my 2001 X5 - and saw for the first time that the vertical area at the rear of the roof panel, that is normally hidden by the top of the tailgate, has started to rust. In fact closer inspection makes it look like it was never painted properly from day one..

Anyone else noticed this on early X5s? (Mine was built in late 2000)