(1) It is no defense to a prosecution under sections 18-8-502 to 18-8-504 that:
(a) The defendant was not competent, for reasons other than mental disability or immaturity, to make the false statement alleged;
(b) The statement was inadmissible under the law of evidence;
(c) The oath was administered or taken in an irregular manner; or
(d) The person administering the oath lacked authority to do so, if the taking of the oath was required by law.