Ubuntu/Canonical colors are Ubuntu orange and Canonical aubergine. None of this colors has any role in the latest Canonical designs. None of this colors as well is present in the UI I think apart of Ubuntu logo button and Ubuntu Store icon. It may be present also in some apps that hasn't been updated for a long time. I think that we retain the orange Ubuntu logo and Ubuntu wallpapers as long as the Ubuntu Touch name is kept. If the decision to change it is made or we are forced to do this, then the new branding for the OS should be created, consisting of new name, new logo and colors for it.