If you look at all the photos, you will see a very wide variety of shades, all of which the Quartermaster Corps called "olive drab".
It is not possible to determine the effects of nearly 100 years of aging as well as possible re-dying in some cases, so the original colors are still something of a mystery. Still, it seems pretty plain that webbing colors were not at all standard throughout this period.
I have seen M1910 belts with both rimmed and rimless eagle snaps, so it seems the transition to rimless occurred while these were in production. Likewise M1909 belts can be found in both khaki and olive green, so the color transition seems to have occurred while these were in production.
It seems unlikely that any doughboy ever was issued a complete matching set of web equipment.