The pommels were often stamped with the initials of inspector Daniel Reynolds ("D.R."), but not always. The quillon was stamped with the serial number, in your case 22M/300. The "M" indicated "thousand", so your cutlass was number 22,300. Some cutlasses are found without a serial number. These are believe to have been purchased for the Revenue Marine Service (predecessor of the Coast Guard) . The 300 cutlasses purchase for the Army also lack the serial number. The serial numbers were used throughout the war and were not supplanted by rack numbers. If your cutlass grip is original, and not a rewrap, it is quite unusual. Shortly after the end of the war, The Navy had the wire removed from the grip and the leather jacked and coated with a tar-based substance to protect them from corrosion.