Hey Rick...I have a 550F and love the original exhaust.
FYI - the exhaust was not made by Honda, their vendor made it, worst part on the bike! Honda did not expect us to be riding these bikes 45 yrs later!
My muffler has a hole the size of a dime near the end, I searched for a long time for one and finally found what I thought was one. Turns out it was not for a 550 but for another bike. The part number is HM388, fairly certain it is for a 360T but is very similar in looks and size to the 550F muffler. With a minor modification to the mount [included] I think it could be fitted and would be much better than an Emgo. At this point, I don't see me using it.
Let me know if you have any interest and can send you pics, its in pretty good condition.