I am looking at buying a Da Vinci 3750 in yellow gold and there are a number of them available for sale, but a lot of them don't come with the original papers or the original box. I can't understand why the purchaser wouldn't keep these (for such an expensive watch), so it leads me to think that they might be stolen. So should I buy a pre owned watch if it doesn't come with the original box or papers? (even if it comes from a reputable dealer?) (but I suppose that even if it does come with the box and papers then it could still be stolen)