(1) If the spouses have specified in a joint will, by which they reciprocally appointed each other heir, that after the death of the survivor the estate of both is to devolve to a third party, then it is to be assumed, in case of doubt, that the third party has been appointed the heir, for the whole estate, of the spouse to die later.
(2) If in such a joint will the spouses have directed that a legacy be given that is to be performed after the death of the survivor, it is to be assumed, in case of doubt, and that the legacy is not to devolve to the person provided for until the death of the survivor.