his eyes were pinkish/red. All forms of ditule genes are a form of albinism, there may not be any full albino horses but that doesnt make it impossible, I've researched and reseached and there are no FULL albinos in any organism I looked at, even humans. Some albinos have even brown or green eyes.
Here's some information about the difference between albinos and double dilutes:
oh and in the UK, we do call all dun looking horses DUN, we don't use buckskin, genetically it may be different but the only use we have for colours is to describe them.
And there are other uses for colors. For example, if you owned a buckskin stallion and promoted him as a "dun" and somebody bred their black mare to him hoping for another dun or a grullo, they might be unpleasantly surprised with a smoky black foal. Not that it should matter, but the client might be pretty unhappy with you.