What year is this penny? The reason I ask this is that with modern plated coins it's more often plating dysfunction that
Cuds per se. Looking at it I think it's a zinc penny that's been copper plated over ... something but I have no way to define further on low res images.
The zinc might have had rim damage before it got copper plated which smoothed it out etc.
If it's a non plated coin and the rim shows no deformation then it's likely a
Cud.