Each master plumber shall display: the master plumber license and the license number conspicuously in the principal place of business of the master plumber; and the license number of the master plumber license on each vehicle used on the job for providing plumbing services. Each holder of a limited master plumber license shall display: the limited master plumber license and the license number conspicuously in the principal place of business of the holder of the limited master plumber license; and the license number of the limited master plumber license on each vehicle used on the job for providing plumbing services. Each holder of a propane gas fitter certificate shall display: the propane gas fitter certificate and the certificate number conspicuously in the principal place of business of the certificate holder; and the certificate number of the propane gas fitter certification on each vehicle used on the job in providing propane gas services. Each holder of a master natural gas fitters license shall display: the master natural gas fitters license and the license number conspicuously in the principal place of business of the license holder; and the license number of the master natural gas fitters license on each vehicle used on the job for providing natural gas services. Except as provided in paragraph (2) of this subsection, a county or municipal corporation may not require a person licensed under this subtitle to display a county or municipal corporation certificate number on each vehicle used on the job for providing plumbing, natural gas fitting, or propane gas fitting services. This subsection does not apply to Baltimore County or the areas in the State under the jurisdiction of the Washington Suburban Sanitary Commission. Each licensee shall give the Board and any appropriate licensing authority written notice of any change of name, address, or employment from that which appears on the current license, at least 10 working days before the change is to take effect.