I am by far an expert on the braiding color, but I will say in the more protected areas of my 69/70's, above the wheel well, behind the passenger panels, it has been very dark, if not black in color. Black items are not always 100% black. They are dyed/colored with other dark colors, such as blue. They make it very, very dark so it looks black. Over time the color, ink, dye fades and its not as dark as it was orginally. I am sure Jeff, Bob and others will correct me if I am wrong, and going by Jeff's photos, the braides were originally suposed to be black in color.
I recently saw another post were the person was asking where to get the replacement white braiding for his rear wiring. Just an extreme case of the braiding material holding up after all these years but the color being totally bleached/washed out leaving the fibers white.