Should be the Model 1873, and should be so marked either on the top tang behind the hammer or on the bottom tang under the lever. sales@countrygunsmith.net
on the bottom of the barrel and reciever.
On the bottom of the receiver in front of the loading port
Check the receiver sides and bottom and the barrel
Check the receiver and bottom of the barrel
Look on bottom of receiver and barrel
The barrel, bottom of receiver, and the slide. All should match. If not, you have a gun that was built from different lots.
Slide the Top Lever to the right to open the chamber. Turn the shotgun upside down. Look at the end of the barrel between the receiver and barrel. Get a flashlight and you'll see a series of numbers stamped in the bottom of the barrel.
Iron Horse - 1966 The Pride of the Bottom of the Barrel 1-5 was released on: USA: 10 October 1966
50-100 USD
It's impossible to tell from this what your question is. Please rephrase and try again.
There is a small double ridged blued sliding latch on the bottom of the receiver just behind the forestock. Pull/slide it rearward and the forestock drops down about 5 degrees. With the forestock released this little bit the barrel can be removed from the frame. Then slide the barrel forward out of the receiver. The forend does not disconnect from the frame without further steps. Reassemble in the reverse order. Be sure the barrel is oriented so the lug on the bottom middle of the barrel fits/slides into the bracket fit on the forend.
Mismatched gun, and an incomplete serial number on the receiver.