I have a Falcon frame which, after seeing this thread, I'm sure is also a Black Diamond. It has no decals except for the Ernie Clements head badge (sticker), which I have managed to get off without damaging it. (You can see it in the photo below, perched on the bb).
The frame number appears to be C27200 (?). No idea what year that would be though. Its rust free but the paintwork could do with redoing.
I'm in two minds whether to powder coat and buy decals for it or not, because its a 23" and slightly too big for me.