My son is out of town - he just bought a new 06 4 door SHORTBED - not a megacan. We ordered a top for him and told the guy it was a shortbed but didn't mention that it was a 4 door. Can I assume that the shortbed on a 4 door is the same as a regular cab model or is there something special about the 4 door that would make the shell different????????? I mean is the back of the window the same etc?????