I think we must remember, that what is put on registration papers as colour of a given horse, is not necessarily true. It is often just what the breeder thought
the horse looked like - often at birth or very young. Tons of horses have been registered as chestnut when babies, when in fact they were grey. Also silvers registered as grey. In Miniature Horse pedigrees and registration, we constantly see colours as something they actually couldn't be. It's fun to guess, but the only way to know the truth, is to test.