I have several Spanish Sidelocks. They were made from the 1950s through the 1970s. Generally, the colors are still nice, but with some evidence of fading. I'd speculate it takes decades of handling, cleaning, and sun exposure for the colors to disappear. Consider what the average 100 year old Parker (or other Vintage gun) looks like now, the ones which have had lots of use.

I prefer wood to plastic, leather to nylon, waxed cotton to Gore-Tex, and split bamboo to graphite.