A duly authenticated copy of a will proved outside of the Commonwealth according to the law of the place of probate may be offered for probate before any register having jurisdiction, and letters testamentary or of administration with a will annexed may be granted thereon as though the original will had been offered before such register. If, in addition to such copy, there shall be produced a duly authenticated copy of the record of the probate proceeding of the original instrument, the will shall be entitled to probate in this Commonwealth and appropriate letters shall be issued thereon without the production or examination of the witnesses to prove such will, unless the will was probated outside of the United States and the record shows or it is satisfactorily proved that an essential requirement of Pennsylvania law for a valid will has not been met. If the will was probated outside of the United States, the probate proceedings may be supplemented by the submission of additional evidence to the register.