My friend Martyn Boogaarts (Robotica), had the chance to put his hands on a couple of these new 'Axle 3 with Stud' (6587) and sent me a photo.
There we can see one, together with its 'Dark Gray' and 'Dark Bluish Gray' old brothers and one Tan axle pin. Unless there is here some mistake and this is not the final production part, it looks the newest element is not Tan colored!
From the photo coloring, which may vary a lot with the lighting conditions, it is not easy to say if it is using any of the already existing and active colors (some kind of Orange or even a 'Dark Tan') or a totally new color.
Perhaps we will need to wait and see.