Do Maya's triangle counts matter, or only the poly counts?

I know this question seems redundant, but I did a bunch of searching and didn’t find anything that was quite what I’m looking for, so please bear with me.

In Maya, I have a triangle count and a face/polygon count. I understand that when I export my mesh as a .fbx files, I can either export it as quads or triangles, and if I export it as quads, UE4 will automatically convert the mesh to triangles at import time.

Essentially, my question boils down to this: Will the .fbx file include vertex information which UE4 will use when drawing the triangles, or will it simply include information about the quads that UE4 will use, presumably largely by simply splitting them?

The reason this seems relevant to me is that the mesh in Maya might have extra vertices along a straight line that don’t actually change the shape in any way, so I need to know if I should be cleaning those up. Thanks in advance!