Clipping does mess with the color of a horse.
Only color combinations with sire and a black(pinto) dam is smokey black, smokey grullo, black, grullo.
We have a coming four year old Tovero mare. Sire is smokey grullo(Homozygous black, carries splash(usually only shows on pinto mares he is bred to). She is listed as a black pinto on her papers. First time clipped, as a yearling, looked like she was a smokey grullo. When we clipped her last year, as a 3 year old, she looks black. But, the hairs in her ears are smokey. So, I think she is a smokey black. Will get her tested.
Her half sister is the same way. Same sire and the dam is solid black. Their first filly(reg bag-deceased) was a grullo. The filly from last year looked to be black when born. Still black when clipped at 3 months. Before being clipped at 6 months, her coat looked like her sire(smokey grullo). When clipped, she looked black again. Now she has her winter coat and it looks between grullo and smokey black. We are going to get her tested, but think she is a smokey black. She has no dorsal strip for grullo.
We have another coming two year old. Her sire is Perlino(homozygous black) and her dam is black(homozygous black). Color calculator says 75% buckskin, 25% smokey black. She is a buckskin because she has the dorsal strip. The strange thing is she has a roan look to her. We are going to get her tested, but we think she got a silver gene from her sire. She looks like a silver buckskin. Her full brother looks exactly like her.