More information would help to elicit the most helpful answers.
People here know nothing about your bike, or you (ie your knowledge of Nortons or mechanical ability, etc).
Describing an abnormal noise is difficult. But ‘rattle under compression or rebound’ could be many, many, things, from fork internals to mudguard stays, to floating discs, to steering head bearings and more.
This forum IS the most tech savvy for Norton Commandos that you will find. No question. I certainly wouldn’t have got what I have out of mine without the expert, and none expert, help I’ve received from this forum.
So I’d like to welcome you to this forum (and to Commando ownership assuming you’re new to it) and respectfully suggest that more informed questions, and a little more patience, will definitely serve you well should you choose to remain on this forum.