Yes, the noun potato is a common noun, a Word for any potato of any kind.
A proper noun is the name of a person, a place, a thing, or a title; for example:
- Delaney Alward, 2012 Little Miss Potato Blossom, Maine Potato Blossom Festival
- Potato Creek State Park, North Liberty, IN or Potato Mountain, Ouachita National Forest, Richland, AR
- Mr. and Mrs. Potato Head (toys)
- Sweet Potato Heaven (restaurant), Cullman, AL
- "Who Made the Potatoe Salad?", 2006 movie starring Daphne Bloomer
- "Potato People" (novel) by Angela Wright
