The case number tells you if a watch is a chronometer or not, and a few other things too like is it supposed to be waterproof. A mismatch between case number, dial or movement means some pretty big meddling with the original recipe. That can be a movement swap or redial. Not sure here but it’s always best to start with the assumption that a black dial is a redial then prove otherwise. This one isn’t looking good.
Now, personally I don't care if it's a redial or not if it looks good enough (because chicks won't know the difference anyway, which is always good to factor in when spending money)
about 700€ "Good" being subjective of course.