Weekly rewards rotation

I don’t know if it has already been asked, but do the weekly final rewards given by completing all the challenges have some kind of repetition after a few weeks or are they always unique and are lost forever once they expire?

I’ll give a practical example: if I missed the Willow Tea coating, will it come back in the future as another weekly reward?

I certainly hope they rotate because if they have to keep adding challenge exclusive items every week for x amount of years, we’ll end up with a lot of lame name banners and emblems and colors that nobody want.