(a) Exhibits shall be of such size as not to encumber the files and records of the agency. They shall be limited to facts material and relevant to the issues involved in a particular proceeding. The presiding officer, at the request of the person introducing an exhibit, may instruct the hearings reporter to make a copy and return the original. The copy shall have the same evidentiary value as the original.(b) If an exhibit has been identified, objected to, and excluded, the offering party may elect to withdraw it and have it returned. In a contested case, if the excluded exhibit is not withdrawn, it shall be given an exhibit number for identification, endorsed by the presiding officer with the ruling, and included in the record for the purpose of preserving the exception.