Frome the LC Smith Collector's page:
L.C. Smith serial numbers, as they are related to year of manufacture, are confusing. Serial number information before 1890 is not available. During the period of 1891 to 1916, many numbers are not sequential with blocks of overlapping numbers assigned to different types of shotguns, such as hammerless ejector guns. Starting in 1917, serial numbers of all types, gauges, and grades are intermixed. Adding to the confusion is that some pre-1913 ejector guns have an “E” at the end of the number, while others do not. Others have the suffix “R” (on both regular and featherweight frames). Many other inconsistencies occur. Serial numbers for the L.C. Smith Gun Company (1946-50) started with FWS1 and ended with FWS 56800. Serial numbers for the period of 1946 through 1950 include Hunter and Fulton shotguns. Serial numbers of guns produced by the Marlin Firearms Company (1968-71) had a prefix of FWM. The data in the following table were adapted from Brophy (1977). Unfortunately, serial numbers for hammerless non-ejector shotguns from about 23000 to 30000 have been lost. You will need to know if the shotgun is pre-1913 or later gun because some of the early serial numbers were repeated in later years. You can determine if it is a pre-1913 or later by comparing information given under Grades of Shotguns on this website. With a little time and perseverance, you should be able to determine the year of manufacture, but remember that all serial numbers are not in the records.
