A Cud will always touch the edge of the design. That's part of the definition of a Cud. This piece sounds like a small die chip.
There is master die doubling on many 1958 cents that shows as a partial extra upper curve on the top-left area of the 8. Sometimes it is well defined and other times it looks more like a small blob. No premium value, they are extremely common.
There is master die doubling on many 1958 cents that shows as a partial extra upper curve on the top-left area of the 8. Sometimes it is well defined and other times it looks more like a small blob. No premium value, they are extremely common.



















