If you have a lot of lip down near where it attaches to the rear of the truck you have a bad set. I sent my initial set back because they weren't trimmed and it was an obvious difference once I received the second set.
I ended up sending the second set back along with the first because the fitment with my rear mud flaps wouldn't work correctly.
I also felt the plastic was pretty thin and cheap. I'll end up going line-X on my rears eventually. Probably do it myself as others have done.
I sent my first set back and looked at the pictures on line of the updated ones and decided not to re-order even though they sent me a 10% off coupon. It would be a pain to try to do them with the flaps as well I suppose. I'm thinking line-x as well but my guy says $400 to do it. Im not sure what to do now. This is one thing that I feel not so comfortable in doing myself so I might just cough up the $. I might even decide to Line-x my skid plate who knows. Its not as bad as a red push start button right?