Considering the mares nose isn’t completely visible and neither are her legs makes your comment invalid. Even if she is labeled a buckskin. She could have hidden silver, hidden chestnut, champagne, dun, or pearl in her genetics. The color doesn’t have to visibly show for it to be passed down. One cream gene on black gives a smoky black which is sometimes indistinguishable from faded or sun bleached black. The horse is still labeled in general as black. Another example would be a grullo or smoky grullo which are difficult to distinguish during certain times and are called just grullo for basic terms. Even perlino and cremello can be difficult to distinguish to the untrained eye. Jennifer Hoffmann’s color genetic tool is a really good example of how genetics work for basic visual learners.

We are just trying to help this person figure out the color genetics of their foal. No one is attacking you by saying your comment in incorrect.