Hi ahanford,
I had sent an upload link a few hours ago. (Private Message).
The question would be, are these polygons, in your case that is visible from both sides (v. single-sided polygons as in game-engines), or are they double there? I have also used applications that had two normals per polygon. I ask as I have seen that term was used in the past in various ways.
If you take a copy of it, and while the object is active, what is the Structure Manager telling you? How many points has the mesh?
Now, use the Mesh> Remove> Optimize…
Has the number of points changed?
All the best