Any person of sound mind eighteen years of age or older and being in the armed forces of the United States of America, in active service at home or abroad or being a mariner at sea, may devise, dispose of, and bequeath his goods and chattels or property, real and personal, anything in this chapter to the contrary notwithstanding.
Any will executed prior to July 23, 1968, which conforms to the requirements of this section shall be valid; provided, however, that the testator of said will must be alive at said date.