Welcome Brandon. If the 1904 is on the trigger guard extension, you have a graded gun from either about 1897 OR 1919 OR a 20g from about 1909. Open the gun to cock the hammers, then remove the forend and the serial number will be on the flat part of the barrels and the action. The grade will be either a number or a letter. Look on the home page under 'Shotguns' and you can identify the grade and date of manufacture. Also check the FAQ section. You can get more information by requesting a Research Letter http://www.lcsmith.org/shotguns/researchdivision.html Please have the gun evaluated by a doublegun specialist smith before using.