Bought the film at a brick-'n'-mortar Barnes & Noble, rather than online, thinking this was the "proper" one. After going online, however, I discovered that the one-disc version isn't available.
It's possible B&N is favoring online over retail, not allowing the two-disc in the stores (though I may be wrong).

It's possible B&N is favoring online over retail, not allowing the two-disc in the stores (though I may be wrong).