I'm afraid only classic colours will be on the proper Bays line... Hope I'm wrong.
I doubt that Mulberry is going to use new colours on the classic Bays; after all, the whole marketing point of retaining the classic Bays is because customers didn't want it to change.
Indeed, many Mulberry fans here have very firmly stated that they didn't want the classic Bays to change. It's probably expecting a bit too much from the marketing team to hope they will parse that as we don't want it to change unless it's to new colours which have never been used in a Bays before; why should they?
Though it's always worth asking if there are any plans to produce the classic Bays in non-classic colours; if there's enough demand the marketing team usually respond