The Board shall establish a program to allow an investigator appointed under paragraph (20.6) of subsection (c) of Section 4 who is honorably retiring in good standing to purchase either one or both of the following: (1) any badge previously issued to the investigator by the Board; or (2) if the investigator has a currently valid Firearm Owner’s Identification Card, the service firearm issued or previously issued to the investigator by the Board. The badge must be permanently and conspicuously marked in such a manner that the individual who possesses the badge is not mistaken for an actively serving law enforcement officer. The cost of the firearm shall be the replacement value of the firearm and not the firearm’s fair market value.