Actually, Just because it is in the free stuff, for either commercial or non commercial use, doesn't mean it is free to use in any way you want. Quite possibly, it is only free if you use it the way that it is proscribed by the author. Any changes or alteration may require a for-pay license. I'm not saying thats the case, only that it MAY be. Best contact the author and ask his permission, or re-read the license that came with the texture to make sure your use falls within the guidlinese the author intended.