Not really. I have over 30K on my dresser's exhaust. They make 2 different types. A SE one is flat & round like a washer & about1/8-3/16 thick. The other is stock however is thicker & tapered to the inside. I like the stock one better, P/N 65324-83B at $6.85 each. it seals better for me. Don't know the SE P/N
tourbox
If you have signs of soot around the flange and head then you have a exhaust leak. Changing the gasket and torquing it to it's proper torque value should fix your issue.
Bluing on the head pipe close to the engine is normal i've never had a bike that didn't. heat shields normally will cover the area where the bluing occurs. A good chroming job will reduce it and cheaper chroming will blue more in my experience.