It isn't so far fetched an idea, I mean if you want to be utterly screen-accurate, technically the KotCS whips were dyed by the production team to achieve that distinctive CS look.
Direct from the main Indygear site:
With that said, I've been planning on dying an upcoming bullwhip for the CS look, but I don't know where to start. For complete screen accuracy, I suppose I should go with the dye that Colin Dangaard provided De Longis, but any ideas what that might be? Or any specific dyes that would work well on a bullwhip for that matter?Some of these screen used bullwhips appear with darker knots this was a result of dyeing. The responsibility of ageing and weathering the whips went to whip coach Anthony De Longis at the request of the films prop master Doug Harlocker.
“Terry's whip (the one's that Colin Dangaard arranged) were lighter in color and Doug said the whips needed to look old and worn and to match the colors of the prop whip he had initially given me. I used two coats of a leather dye that Colin gave to me; the one he uses to dye his excellent saddles.
I dyed all the Jacka whips the same so they would look aged at the request Prop Master Doug. I don't know whether they did any additional dying on set (to darken the knots) or whether just the normal wear and tear and dragging them through the dirt during filming and adding Dubbin to keep them moisturized changed the color slightly. The latter seems most likely." —Anthony De Longis
I'm surprised nobody has asked this question before, but in a quest for complete screen accuracy, enquiring minds have to know!