Mines also welded. For the fleetsides its really the only option due to how it mounts. it will actually be a little wider than the hole it goes in. I think they do this so it can be welded. you could weld side mounting plates on the roll pan and use some bolts with shims to mount it. Your going to have to paint the roll pan anyhow and the factory seam at the bed end cap is a perfect place to hide the tape lines. In the long run I think you would be happier with it welded and filled smooth. Here is mine
