(From Breyer History Diva, 2009.)
Documentation is more of a factor in the criteria of Rarity and Desirability. As I hope I've demonstrated in some of my posts, there are many models that are more – or less – rare than we perceived them to be. Not every judge is going to be as well-versed in the scales of rarity for every single model. Faced with a large or involved class, they may opt to ignore what may appear, at first glance, to be a more common version of a model.
The original release of the Midnight Sun is an excellent example here: there are several different versions of the original release in black. One of them is actually rather scarce: the earliest version, which came with distinctly light gray hooves. (And quite different than the more common gray-brown hooves version.)