Yes , the seat was upright to get to the front bolts. The floor is pretty flat. Within an inch ish. I used 1.5 x .75 aluminum tube to get the bolt heads below the inside box height. If that makes sense. I also used a few 1/2" this nuts larger than the bolts for spacers. I used the original bolt holes. The carpet also adds to the unevenness. If you need more i will try to help.