Those plants are definitely done.
Leaf color has nothing to do with ripeness of bud. Period.
Most of your trichs are probably amber by now, because that looks like it's past its harvest time.
I don't really go by trichs though, I know it's the best method, but I've always gone by pistils and if the buds "looked done" to me. It's something that you gain with experience. What was your nutrient regimen? Did you overfeed the shit out of your plants? (doesn't look like it because the leaves look healthy and the plant looks pretty damn good). If no to both of these you don't really need to flush.
The importance of flushing is to get the excess salts out of your medium. You can tell when a plant needed to be flushed because the buds will taste really "spicy" if not cured properly. This is because most liquid nutrition (excluding teas) gives nutrients to the plant by skipping the exuding process of microbes and putting nutritious salt directly in the rhizosphere. What isn't used is left in your medium and can build up the more and more you use nutes. If you didn't use nutes, or you barely used any at all, you probably do not need to flush.
