This is a new hard to find dust cover (also called mortise cover) ORIGINAL Winchester model 1876. It has the finger grooves milled into the sides. It fits the 2nd and 3rd models (serial number 3,000-25,250 for 2nd model and 25,250 to Forearm of production) that has the rail attached to the top of the receiver with 2 screws. You will need the dust cover stop (wp608-a) and dust cover stop screw (wp617-a). The dust cover spring (wp610-a) sits in the rail and puts tension on the dust cover when it is pulled back to keep it from falling forward.