Rotate the *blade tag sounds about right - tags are triangles representing directions (the blade's one in this case), though as the direction is determined by the indices (i.e. order) of the vertices which is kinda hard to find out how it'll turn out so you usually have to experiment until it points in the right direction. You can take a look at the model (and other sabers) in the glm viewer ModView with "Show actual tag surfaces" turned on to get a better idea of how it works. The second problem is related to surfaces being one-sided, i.e. they have a visible front and an invisible back, like patch-meshes in maps. So you'll have to select those topmost polygons and do something like "flip normals" - I have no idea what it's actually called in gmax though as I do not use it. Oh, after re-reading part of your post I just saw you're using Blender - just stick to it! There's an md3 exporter for it that works just fine, although it hasn't been updated for the latest versions yet (I'll get around to that eventually), and I did some
on creating a saber with it.