Jim, My (limited) experience is similar to yours. My "large" ABs are all 350/no frame, the skinny ones are 350/frame. I've often scratched my head about this. I don't have any 460s.
Baker -- no frame (I also have a McQuillian that is large, but don't have a scan handy)
Huggins -- 350 w/frame
Speaker -- 350 w/frame
