Actually, if a record from the 1940s buzzes when you tap it, then it has a crack somewhere. Honest dealers specify which 78s have hairline cracks. Rim chips come in many shapes. The worst is the rim chip that affects the opening grooves of a record. Such holes cause skipping, or the needle gets stuck here.
Collectors care about labels and pay less if labels are defaced by stickers or writing.
I have some 78s signed by Elizabeth and William Wheeler. Tim Gracyk's main page listing all articles.