This probably explains a lot of the problems people are reporting with smoothing groups...A 3DS mesh does not store any normal data so normals must be computed by the target system. Some importers might compute the normals incorrectly resulting in the appearance of flipped textures.
A good fix, btw, is to use something like UVMapper Pro, which is what I use to do uvmapping with, to fix the models. You can use this tool to weld all the verts of your model, then use the Split By Angle feature to split out sharp-edged corners. I've been using this myself, and it works great!
And no, I'm not related to, paid by, etc., the guy who makes UVMapper
