An Act amending the act of May 22, 1945 (P. L. 837, No. 337), entitled, as amended, "An act providing for and requiring in certain cases preference in appointments to and retention in public position or on public works for honorably discharged persons who served in the military or naval service during any war or armed conflict in which the United States engaged or served therein since July 27, 1953, or hereafter so serves including service in Vietnam; and in certain cases for the widows and wives of such persons," extending civil service preference to members of the Pennsylvania National Guard.