Not many are ready "out of the box". FPSC kept (most) entities separate from their respective meshes and textures. They can usually be easily converted, however, it just depends on your willingness to spend the time. If you have an entity you wish to convert, you need to gather together it's .fpe, .bmp (usually in the entity folder), the mesh (usually in the meshbank), and the texture (usually in the texturebank, of course, see the trend?). You need to place them in the same folder in the Reloaded entitybank directory. You then need to alter the .fpe to call lua scripts instead of .fpi scripts. Reloaded asks for textures to be named and referred to as diffuse = "MyTexture_D.dds", normal = "MyTexture_N.dds", and specular = "MyTexture_S.dds". This is not at this time an absolute, but I fear that maybe it will be in the future. So far, I have found that a simple diffuse texture works in a few different formats (.jpg, .png maybe more, think DBPro if you've ever used it). Multiple textures also work. (just don't specify a texture in the .fpe). The model packs are definitely worth the price to me, personally. I've bought most of mine on special (always a great deal so far), and converting, while time consuming, is way less time than trying to recreate one from scratch!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics