As far as I know the bolt should just come out with a little brute force to shear the weld but I've never taken mine out for one very good reason; TomL took his out and promptly went mad and deaf. He put it back in a couple of days later...
Richard (richtea) discovered his very noisy, new-to-him K13S had no dB killer fitted. Dealer supplied one and hey-ho, peace and relative quiet was restored to Abingdonshire, Newburyshire, Miltonkeynesshire etc. etc.
I understand your inquisitiveness but in your position I would leave well alone and give the neighbours some peace and quiet.