Attached is a picture of what I think is a Benelux Mark 7. It is not complete, as you can see. The chain thingie that goes in the lower hole is missing - does this piece thread in or do you have to disassemble the derailleur to attach it? The flat spring looks a little intimidating to me and I'd rather not disassemble the whole thing if I can avoid it.
The claw and bolt at the top is also missing, but the bike that I'm thinking about putting it on has an integral hanger - can this derailleur be attached to the hanger directly, and should it pivot or be held fast at that point?