“ After any Naval or Marine Corps unit is so cited on two or more separate occasions for outstanding performance in action occurring on or after October 16, 1941, such insignia shall become part of the uniform of such unit, and shall be issued to officers and men who may thereafter become members of such unit; and such insignia may be worn at all times by individuals who were attached to the unit so cited on one of the two or more occasions in connection with which the citation was issued, whether they thereafter serve with such unit or with a different unit. ”