§ 497. Construction of certain local option provisions in exemption statutes. 1. Population restrictions. When an exemption statute makes one or more options available to municipal corporations having a population within a specified range, and the governing body of a municipal corporation adopts a local law or resolution exercising such an option while its population is within the specified range, a subsequent change in the population of the municipal corporation that places it outside the specified range shall not render such local law or resolution ineffective or invalid, nor shall it impair the ability of the governing body to amend or repeal such local law or resolution to the same extent as if its population were still within the specified range. Provided, however, that this subdivision shall not apply to any exemption statute that expressly provides that a local law or resolution adopted thereunder shall become ineffective or invalid if the population of the municipal corporation subsequently experiences a change that places it outside the specified range.

2. Filing provisions. When an exemption statute makes one or more options available to some or all municipal corporations, and further provides that a municipal corporation adopting a local law or resolution exercising such an option shall file a copy thereof with one or more state agencies other than the department of state, but if such statute does not expressly provide that a local law or resolution exercising such an option shall not take effect until a copy thereof is filed with the specified state agency or agencies, then a failure to comply with such filing provision shall not render such local law or resolution ineffective or invalid.