Okla. Stat. tit. 64 § 1030
The Secretary of the Land Office shall cause all mail received by the Land Office to be opened by some employee designated by the Secretary, assisted by two other employees not connected with the cashier's office, whose duty shall be to examine all incoming mail and make a proper reception record of all monies received. The reception record shall be delivered to the cashier. The entries on the reception record shall be made at the time of the opening of the letters and when completed shall be signed by the maker and witnessed by the employees assisting, who shall also sign. All cash and cash equivalents, together with the reception record, shall be immediately delivered to the cashier who shall give a receipt therefor by signing the original copy of the reception record, and who shall make proper entries on the financial records of the Land Office showing the amount so received. The Secretary to the Commissioners of the Land Office and the cashier are charged jointly and severally with the proper keeping and it is hereby made their duty to see that the above and foregoing reception record is correctly kept. Alternatively, or in addition to the procedures set forth in this section, the Secretary may also purchase lock box collection services from an appropriate vendor for the handling, collection and processing of mail. Lock box services may include collecting Land Office mail from a specified post office, sorting, totaling, and recording payments, processing the items and making deposits.
Okla. Stat. tit. 64, § 1030