Some online resources for researching banjo serial numbers are AcousticMusic.org, Banjophiles.org and Fender.com. These website have serial and model numbers listed for banjos manufactured by companies such as Gibson, Bacon and Day, Fender, S.S. Stewart, Paramount, A.C. Fairbanks, Weymann and Ludwig.
Banjophiles.com offers an extensive listing of serial numbers for pre-war Gibson banjos that date back to the 1920s, and the site also provides serial numbers for post-war Gibson banjos. Visitors to this site can find links to these various information pages by going to the home page. This website also gives a wealth of information on the different styles that were manufactured between 1922 and 1937.
At AcousticMusic.org, there are serial numbers available for other brands of banjos, including Bacon and Day, S.S. Stewart and A.C. Fairbanks. Some serial numbers listed for Bacon and Day range from 1906 through 1966 as of 2015. For S.S. Stewart banjos, the listed serial numbers are for models produced between 1878 through 1900. For A.C. Fairbanks, there is also an extensive listing of serial numbers for different years. This website also provides links to the history of many of these banjos.
Fender.com provides model numbers and names for its brand of banjos that were manufactured between 1969 and 1986. Some of these models are the F1080, F1085, Allegro Folk, Allegro Tenor and Artist Plectrum.