Any member of the armed forces of the United States or any citizen of the United States who served in the armed forces of the united nations during World War II shall, upon his or her reemployment by a prior employer within one year after his or her honorable discharge from the armed forces, upon proper proof of his or her service and the length thereof, be given by the employer, in addition to the seniority rights he or she had when he or she left that employment prior to his or her joining the armed forces, additional seniority rights equal to the time he served in the armed forces.