Hi,
I owned an 1968 06c 327/275hp auto. It still had the pipe and shield, never had a screw in it. Now I don't know if it was replaced before my family owned it (early 80's) or if it was replaced when it had the engine stop lift cable installed (recall). I do have another setup from a '68, I don't know the build information, it also has never been screwed together.