Yep - running rich and also might be worn valve guides or failed valve stem seals to put down that much carbon.

To clean, bring the piston to the top of the bore, and if the deposits are fairly soft, use a piece of hardwood (oak, or ash or similar) about 1.5 time as thick as a paint stir stick. It needs a good sharp edge like from a fresh table saw cut. Vacuum and wipe out. Do the heads the same way. If the carbon is real hard, a piece of brass will work. Neither will do damage to either the piston or head.

As far as the scuffs on the cylinder walls, if you can't catch a finger nail, they are only scratches. If you catch a nail - another decision has to be made - i.e. do I tear it down and hone a thou or two and clean most of it off or do I $pend the big buck$ for another rebore