Yes, they were viewable in Maya. Due to the limitations of the HLSL plugin, however, the culling was applied post-skin instead of pre-skin. In consequence, the culled area didn't deform with the mesh. We didn't make any investment to solve that, because we could already more easily see the results in our model viewer. There, it was easy to quickly cycle through the hundreds of animations of the horde members to see how the wounds worked in motion. We also had the ability to activate them in-game through the console to review them en masse, seeing the same wound simultaneously on a variety of infected.
Here are my slides, which contain more information about the authoring of the wound sets, along with the variation system for the horde: