When I've (once) been on a 767 with an international-cabin on a domestic flight, as I boarded, the cabin crew looked at my boarding pass, looked into his iPad and then asked if I'd like to sit in the CW cabin instead, based on my BA Gold status.

I'm half surprised they don't' do the same with the 747, but then again, the 767 can have fewer seats compared to the regular offering, e.g. domestic configured 767, so they're not forced to.