The Enforcement Act of Act of Military Service System Article 4

Before enforcement of the Act of Military Service System and this Act, the Reserved Military Man without certificates to prove his military identity shall be registered under the regulations enacted by the Ministry of National Defense and governed by the Act of Military Service System and this Act.
中文原文 兵役法施行法第4條
兵役法及本法施行前,具有後備軍人身分而缺乏規定證件者,應由國防部訂定辦法予以登記,依兵役法及本法管理。

English translation for reference only; the Chinese text prevails. Not legal advice.