“Local police officer” also includes any officer or employee of a contracting agency other than a city or a county who is a peace officer as defined in the Penal Code and whose principal duties consist of active law enforcement but excluding clerical personnel or those whose principal duties are that of communication officer, identification officer, machinist, mechanic, security officer or are otherwise not clearly within the scope of active law enforcement, even though the person is subject to occasional call, or is occasionally called upon to perform duties
within the scope of active law enforcement.
The provisions of this section shall apply to any contracting agency that is not a city or county with respect to any of its employees who were local police officers within the meaning of Section 20425 prior to its amendment by Chapter 625 of the Statutes of 1975 and in employment on January 1, 1976.
The provisions of this section shall not otherwise apply to the employees of any contracting agency nor to any contracting agency until the contracting agency elects to be subject to the provisions of this section by amendment to its contract with the board made as provided in Section 20474 or by express provision in its contract with the board.