I have a Holton soprano sax made in Elkhorn with the serial number of 19456 which seems too low for the ones you list here. Since is stamped Elkhorn, I am assuming it is after 1918. Did Holton run two sets of serials with one being Chicago and one Elkhorn for a while, or did they have a different list for saxes versus other brass? I have a Chicago euphonium and tuba, but both have higher numbers than the sax.