I've torn my top end apart for a rebuild and there's some visual scoring of the cylinder above the exhaust sub ports. If I run my fingernail across them, I don't feel anything. Is this normal, or do I need to replace the cylinder or replate?
You always tend to get scoring above the exhaust port, but the fingernail test is probably as apt as any, I’d put it back as is with the new piston kit. If you are in any doubt take the cylinder to a trustworthy mechanic.