This horn has been around the block and I think it's pretty old. Seller says he contacted the company with the serial number, but the horn predates their cataloging. Starting bid is $2,000 and there is a make-offer button. I assume he means a higher offer and I have no idea what he will take for it. Personally I could not go very high for this one, but for a low enough price it might be a good bargain for a serviceable instrument.
ITEM SOLD FOR $2,000
https://www.ebay.com/itm/Willson-4-Valve-Compensating-Euphonium/254361661032
-- edit to mark sold --