Tink5775,
Condition is probably as important or more important for valuing a Double Bell than for a modern player.
I have a silver 1941 Holton Double Bell with 5 front action valves, engraved with a "US". Serial 146_ _ _.
It took around $2700 (my priciest horn) to acquire it back in 2011.
It looks great, valves not bad for the vintage. Surprise was a rotten lead pipe one could not see in pics.
Fortunately, my local repair guy had a euph lead pipe in silver.
What you have described appears to be substantially older than 1941 if 11824 is the serial number.
I think the real question on Double Bells is how much is one willing to pay for the existing condition.
The Double Bells are more for our egos than practical playing (I use a Besson New Standard for that)
Good luck hunting for a Double Bell you like at a price you can accept.
Jim
Jim Babbitt
1960s 4 valve and 1971 3 valve Besson New Standards (Denis Wick 6BM) for regular playing
1936 Conn 5 valve 30I Double Bell (Bach 6-1/2AL) General Purpose Back -Up
1924 Buescher 5 valve (the Denis Wick is close) and 1940 Holton 5 valve (Bach 6-1/2AL) Double Bells for kicks.
1860s OTS Saxhorn when history is required (the Denis Wick fits)