Mo. Rev. Stat. § 290.270

The finding of the department ascertaining and declaring the prevailing hourly rate of wages and the public works contracting minimum wage shall be final for the locality, unless reviewed under the provisions of sections 290.210 to 290.340. Nothing in sections 290.210 to 290.340, however, shall be construed to prohibit the payment to any worker employed on any public work of more than the prevailing hourly rate of wages or the public works contracting minimum wage. Nothing in sections 290.210 to 290.340 shall be construed to limit the hours of work which may be performed by any worker in any particular period of time.