Hey Chooch:
Sounds like you've got quite a find. If I were you, I'd suggest tracking down Zig Kanstul at
Welcome to Kanstul Musical Instruments. He used to be production manager for Benge back in its heyday. He produces several high quality horns today in Anaheim, CA. One of the lesser known facts is that Kanstul does repair and refurbishing work on horns. I've got an old Bach and a Kanstul-built Besson MEHA in the Kanstul plant right now being put back in to like new condition. There's probably nobody better to refurbish the horn than the guy who most likely oversaw its original production.
Best of luck to you.
Regards,
Mike