You think it must be shorn? It couldn't just have a mane? I think it's kind of cool to imagine they might have had mutts that developed manes to protect them from throat injuries in combative situations, but maybe you're right and it's more likely the rest of it's fur was shorn short.
I will risk ridicule here and tell ya that I believe it was a short-coated dog with a mane, no grooming whatsoever. Dense, flat coat with a mane and no feathering on the legs and butt. It can happen, I've seen it with my own eyes and I believe that statue to be of a specific "breed" from the greater "molossian" family, one which certainly played a part in the genesis of both the proto-Shar and the southern-wave "alaunt" branch. Whether that "breed" was an ancient hybrid or an ancient source for both is fun to think about, but its statue has been and will continue to be used as an illustration for everything from a Neo to an EM and anything you can think of in between, regardless of how much squinting might be necessary to "see" the similarities, so it doesn't even matter. After seeing the thing in person and experiencing certain truths subsequently, I'm pretty confident in my understanding of this "hound" thing.
One more thing, just as an aside. It should be noted that in many old texts "erect/pricked" stands for cropped. Also, it's easy to assume that dogs represented in art had naturally pricked ears if we forget artistic license and its application to something like cropped ears, depending on the time period. Just something to keep in the back of one's mind.