Any registrant who has been separated from the Armed Forces (including their reserve components) by reason of conscientious objection to participation in both combatant and noncombatant training and service in the Armed Forces shall be classified in Class 1-O-S unless his period of military service qualifies him for Class 4-A. A registrant in Class 1-O-S will be required to serve the remainder of his obligation under the Military Selective Service Act in Alternative Service.