I just purchased a late 50s Conn 6H trombone on e-bay. When I received it I assumed it was a Director because it has the Conn "marching band" logo on it, which I thought was only placed on student horns. However it does say 6H in tiny letter under the slide lock on the bell. I`m wondering--did they put the marching logo on pro horns, or was this one built out of spare parts? Appreciate any info.

I think they did put the logo on the 6H at least, because I found someone selling one and it has the logo. Here is the link, so you can look at the pictures to verify it for yourself.
http://www.earthethics.com/trombone.htm

thanks--that`s my horn allright.