I have a Leer cap on my 08 that I bought used off of an 01, it's rear door fit is good but not perfect, but I am not sure that a 'new' cap on an 08 would fit much better. I am still experimenting with adjusting it for best fit but the door seems to be a little too tall for the newer style tailgate top.
I havent been able to see a new cap on a 08 truck but I think there is probably a small difference in the door size to compensate for the new style tailgate caps.
My truck has the step but I dont think that makes a difference.
The slightly poor fitting door is tolerable for the difference in price for a new cap vs. a used cap.
