This bit (red circle) is a Stub attached to a strip of metal that is held in place by the hose clip on the downward part of the tail pipe to locate the top retaining screw of the heat shield/cover.
great...thanks everyone...yes, I used new copper gaskets...I've been reading those take time to seal and will leak slightly until then???
I DID NOT used the silicone...but now that everything is buttoned back up, what can I do? Is there an easy way to use the silicone without taking everything off again? OR Should I ride the bike and see if they seal?
ALSO, I need to get my tune updated, can I ride the bike gently for 15-20 minutes to drop it off by the tuner?