If you're going to replace the rings, de-glaze the cylinder. Shouldn't take much. Being past the 100-mile mark, it's too late for a "second seating" (pun sort of intended). CT70 cam & rockers are dime-a-dozen parts. Good head castings, with a specifically desired set of casting numbers...not so much. I was thinking that, too. Which one of us should be "very afraid"?