Numbers visible on triggerguards, floorplates and outside of Rigby Mausers are usually serial numbers of Rigby or other British retailers. The numbers on bolts and other small parts, in Texgun's case "17", are the last two digits of the Mauser factory serial number. To verify this Mauser serial number, you have to take the rifle apart. The Mauser number on actions sold to other gunmakers is under the receiver ring, behind the recoil lug, and on the rear wall of the magazine. These are the numbers that have to match, ending with a "17", as Rigby did not care to renumber all parts.