Well...
good and bad,
The muffler didn't survive, tried to drill the stud out but couldn't stay on it and she never broke free. Eventually the guide the bolt was in twisted up and that was the end of that.
I cut the muffler flange adjacent to the gasket with a hacksaw so as not to damage the cylinder.
Couldn't pull the stud from the cylinder exhaust flange, so that got drilled and tapped after pulling the jug.
The good news is the cylinder is saved. It was beginning to score due to carbon in the exhaust port. The P&C will be used again.
If I hadn't pulled the muffler, she probably would have self destructed.