I have come into the possession of what has been identified as a Conn 6D. It's not in the best of shape cosmetically as it was retired from a school band program, but does still play. I don't know the year, other than the case has a 1961 Lions Band sticker on the outside and it has a Mt. Vernon Bach mouthpiece with it. The serial number (as best I can tell) is 821993.
Can anyone give me any leads as to finding out the value of this horn in order to ask a fair selling price? I can post/send pictures if needed.
I still have the sweet old 6D I played in high school in my collection so I notice prices when 6D's come up for sale. You'll find horns on Ebay and the used horn vendors (hornplayer.net and the like) from time to time. The asking prices I've noted in the last few years range from around $500 to $1500. There's one example on hornplayer.net when I check tonight listed at $2000 but that's the highest listing I've seen in a while.
Posting pictures and dating your horn via one of the serial number lists will both be helpful as you look for a buyer.