That's a nice set of K3 exhausts you have - you say they are original? Mine are original too (1977) and have no baffles in the right hand side - sounds like an old G5 250 with the 180 degree firing cycle! Here's mine
http://www.sohc4.us/forums/index.php?topic=2095.0Pedant time.
I see you have an early (two strut) front mudguard - this can't be original?
You also have 550F sidepanels...
Put us out of our misery and post the engine and frame numbers.
To answer your question, don't be frightened about taking off the exhaust clamps as they're almost impossible to clean up on the bike. I've had good success with Solvol Autosol and those green potscrubbers that you get from Sainsbury's.
Jotor: the brackets were all black in the UK, this is a custom paint job.