If a program is adopted pursuant to sections 23-2534 to 23-2544, the county service shall be divided into the classified service and the unclassified service. All officials and employees of the county shall be in the classified service unless specifically designated as being in the unclassified service. Positions in the unclassified service shall not be governed by personnel rules and regulations adopted pursuant to sections 23-2534 to 23-2544. Unless otherwise designated by rules and regulations adopted pursuant to sections 23-2534 to 23-2544, the unclassified service shall include the following:
(2) The county personnel officer and the administrative assistant to the county board;
(4) Department heads and one principal assistant or deputy for each county department;
(5) Members of boards and commissions appointed by the county board;
(6) Persons employed in a professional or scientific capacity to make or conduct a temporary and special investigation or examination on behalf of the county board;
(7) Attorneys, including deputy county attorneys; and
(8) Employees who are covered by the State Personnel System.
Nothing in sections 23-2534 to 23-2544 shall be construed as precluding the appointing authority from filling any positions in the unclassified service in the manner in which positions in the classified service are filled.