Any county employee in the classified service who has held a provisional appointment or provisional promotion continuously in the same class and agency for a period of 6 months as of July 1, 1968, shall be granted regular status in the class of positions in which such provisional appointment or provisional promotion is held. This section shall not pertain to any deputy sheriffs who hold such provisional appointments or provisional promotions, to any employees who are not citizens of the United States, to any employees holding provisional appointments in the class of common laborer nor to any employees holding seasonal appointments.