no, if your plants are healthy why would you rape them of there nutes?! Whenever the pistols grow sometimes a few stray ones will turn amber, it's completely natural. As time progresses and the buds get bigger and swell the hairs will all start turning amber letting you know it's getting mature. As the plants reach it's peak for harvest a lot of times 80% or more of the white hairs will be amber color, but the only real way to tell when to harvest is to look at the trichomes through an at least 30X microscope.