Your horn was made in 1923 and is likely a C.G. Conn LTD New Wonder Series I. The "L" refers to Low (Concert) Pitch, i.e. A=440 which is the standard tuning now used for all instruments. There should be a letter above the serial number which would stand for the the type of sax, such as A"=alto, "C"=C-Melody, "T"=Tenor, "B"=Baritone etc. If the finish is still very shiny, devoid of tarnish, and has a very subtle brass or gold undertone to it, is likely Nickel Plate. Otherwise it might be silver plate