Yes, that's the Adios mold. The second one you linked to is the Haflinger, which is a classic mold (the mid-size, vs. the Traditional size that the Adios is). Adios was released in the late 1960s and has represented many breeds over the years. So they would've wanted it to join their Breeds of the World, I imagine, which is the trad line.
This thought of having one's own mold comes up pretty frequently, actually. People ALWAYS think their horse deserves its own mold. It's very common for, say, a famous horse -- "that sculpture looks nothing like (insert name here)! It deserves its own mold!" But Breyer has to make what is going to be profitable, so it rarely works that way (yes, the molds and development cost tens of thousands of dollars). Popular horses like Black Caviar, Zenyatta, Hickstead, Frankel, etc get dropped right onto existing molds. May not be a perfect likeness, but they try to match the body type.
Breyer has been doing some revolutionary changes in recent years -- they have released unique portrait sculptures of Totilas and Valegro (both dressage horses, go figure!) and American Pharoah -- and have started employing some of the best model horse sculptors in the business to add some new molds (including the aforementioned).
So you have to balance current stock (molds) and colors that have already been released on them, and what you have currently in the line (ie if we're already using X mold for X horse representation in X color, that can't be repeated). Then you have demand (how much -- from toys to casual collectors to serious model horse collectors, and what are those people willing to pay), and what is missing from their portfolio that they could make a profit on. A plain color (ie not a lot of pinto markings etc) on an older mold has much less production cost associated with it.
So who knows? You might see something in the future, if the model sells well. They recently did a Marwari (a very rare breed), and then just did a lovely welsh cob they released last year!

And you can always have a model horse artist custom-paint a Breyer to match your horse
