No and if yours does you need to take it to the vet it might have an infection
If you have brown spots on the roof of your mouth, it could be patches of melanin. Another reason brown spots might show up is because someone smokes.
Cats (and dogs) often have black markings in their mouths and on the insides of their lips that are just normal colorations. This is often the case with cats with multiple colors of fur. Unless it is sore or causing pain for a cat it usually is not a problem.
If the spots are only thru the clear coat the entire roof should be carefully finesse sanded and then reapply clear coat as directed by manufacture.
Strearks on roof
Because white reflects heat whilst black absorbs it therefore a white roof will keep the house cooler as the suns rays will bounce back off of it whereas a black roof will absorb the suns rays.
Probably
Black can be OK. Black with pink spots. Test like this, firmly press with one finger for 3 seconds on the gum, look quick when released it should go from light colored back to black in about 2 seconds, if not there could be a problem such as liver disease and would need to be checked by a vet.
Roof wetting is a Bermuda custom. The participants climb to the roof anda bottle of black rum is either poured on the roof or is shared, or both.
It is normal for some dogs to have a black roof to their mouth; it is simply part of their natural colouration. If the black part looks lumpy or is growing oddly then you should take your dog to the vet.
Sun damage.
If the spots are only thru the clear coat the entire roof should be carefully finesse sanded and then reapply clear coat as directed by manufacture
Black both absorbs and emits radiation better. That would result in the house being hotter in the daytime and colder at night.