Hi, The only company I know of that puts some itentivication on the backs of there liner is Doughboy. For them to warrenty your liner you need a section of bad seam and the section with the logo. That is found where the verticle seam meets the horizontal on the back side.

I remember one other company that had something on the back of the liner, a sticker or something. It was at the top of the verticle seam.

Hope this helps, Dennis