From the photo, the wood appears to be mahogany rather than oak. Mahogany was popular in 19-20C for nicely-made small boxes which were not to be laquered/covered in leather.
Despite the somewhat indistinct royal cypher, it is likely the lock is a basic, unpatented, 2-lever boxlock, made for a wholesaler, who would not allow the maker to mark the product. Other similar such markings are also commonly found, as: ‘secure lever’; ‘patent lever’. These give little clue to the date, but my sense is this one might be William IV (1830-1837). Queen Victoria created Royal Warrants, and from then on, use of the royal cypher was carefully policed.
