It is FSX native, but there are no bump maps or spec maps assigned to the materials, so right now there isn't support for those, even if they were to be made. My plan was to wait until larger-resolution textures could be made (doubling the size of the original texures), and then bump and spec maps would be made/assigned then. That is something I set out to do, almost from the get-go several months back, but I could never get that work finished, so I finally set my sights on just doing the most basic FSX conversion, for now, so that everyone would finally have a true FSX version (despite no bump maps or spec maps). Unfortunately it could take me a while to complete something like that.
I'm thinking that between taking some time today and some time tomorrow, I will try and create some good bump and spec maps from just the existing resolution textures/templates and assign those options to the exterior materials. I'll make the spec maps "neutral", so that they can be used with any repaint, without any side-effects that comes with making spec maps unique to one individual paint scheme. Of course everyone will also be free to make their own spec maps using the already existing paintkit, if they wish.
Still, for the time being, if you're interested, please do still download the above files, in order to fly the aircraft, problem free, in FSX. When I do have the specular and bump mapped versions ready, the files will just be updated and will be able to be installed over the existing files, again. If I can get that done within today/tomorrow, those will be the files I upload to the library.