US Indian Wars Era Cavalry Picket Pin, US Marked

Original era manufacture. Identified as the Lyons Pattern, on page 37, Plate VII, item 3 in 'Horse Equipments and Cavalry Accoutrements' by James S. Hutchins, illustrating plates taken from Ordnance Memo 29 published in 1885.The pin measures 15 inches from the top to the pointed end, with an overall length of just under 18 inches.Clear US markings on opposite sides of the pin, with a property number appearing to be 51 on one side.Scattered surface corrosion as shown, however it does not affect the movement of the looped swivel, and both US markings are quite clear. Scarce piece of Cavalry equipage I would think.