Keep in mind that the red dye was applied on top of the fastener original finish. Thus, red dye on a phosphate/oil nut/bolt will look very dark whereas red dye on a zinc or cadmium nut/bolt will look very light to an almost pinkish color.
John is correct that the dye does not come off that easily. The best example of this is the small wire retainer clips that are used to hold the e-brake housing to the underside (2 at the back, 1 at the front). Whenever I pull an original set off and clean them, I can always find the original red dye.
Regards,
Pete Morgan