A document of gift is valid if executed in accordance with: This subtitle; The laws of the state or country where it was executed; or The laws of the state or country where the person making the anatomical gift was domiciled, has a place of residence, or was a national at the time the document of gift was executed. If a document of gift is valid under this section, the law of this State governs the interpretation of the document of gift. A person may presume that a document of gift or an amendment of an anatomical gift is valid unless that person knows that it was not validly executed or was revoked.