If a person employed by the county superintendent of schools in a position not requiring certification qualifications is assigned to a position under the same superintendent requiring certification qualifications, the employee shall retain all sick leave, vacation, and other rights and benefits accumulated by him at the time of assignment to the position requiring certification qualifications. All seniority and permanency rights shall be secured to such an employee for a period of 39 months from the date of his acceptance of the certificated position. Such an employee shall be eligible to return to and assume the duties of his prior classified position at any time during the 39 months and his return shall be treated as if there had not been an interruption in his classified service.