I have a Remington Model 1889 Shotgun and have not been able to determine what grade it is and it's serial number. I have looked on the underside of the barrel and there is no number but only a unidentifiable marking. I also have tried to disassemble the shotgun and with the forearm piece off the other two pieces will not detach like I've seen others being able to do. What I believe to be the serial number found on the forearm and can see on the other two pieces of the gun is the number 19889 but have not seen other serial numbers like it or been able to look it up. Any help is appreciated.