§ 1223-a. School buses; required identification. All school buses, as defined in section one hundred forty-two of this chapter, purchased, leased or acquired on or after September first, nineteen hundred ninety-seven shall have the area code and telephone number of the owner and/or operator printed in three inch bold type on the rear of such vehicle. Provided, however, that nothing contained herein shall be deemed to prohibit the printing of such information as herein provided on school buses purchased, acquired or leased prior to September first, nineteen hundred ninety-seven.