Unless I misread the serial number chart, this horn is from the late 1890's. It looks to be in terrific shape for a horn of that vintage. The valves are 3+1 (seller says they have good compression). The main slide looks long, so I'm guessing that was a slide to put in into standard pitch (perhaps a factory solder/install or perhaps removeable - I can't tell). Starting bid is $1,999 from a known seller with a very good reputation.
SOLD FOR $1999
https://www.ebay.com/itm/125392873439?ViewItem=&item=125392873439