Are chestnuts a clue to perissodactyl evolution?

I've read some interesting theories, based on comparisons of
enzymes, to suggest that lumping tapirs in with rhinos as
ceratomorpha is wrong and that they are, in fact, more
closely related to equines and should therefore be under
hippomorpha. Any views on the subject? Doesn't the fact that
certain tapirs have chestnuts on their legs indicate a
closer relationship with the horse family or do chestnuts
also exist on rhinos' legs in a disguised form? I'm writing
a report on tapirs as an endangered species. This isn't
crucial to what I write but if their classification is under
scrutiny, perhaps I should mention this. It also has
implications for the kinds of diseases to which they are
susceptible.