Not sure if the 2nd gen were this way or not, but my long bed 2500 has a highly tapered bed. The front is 65 5/8 in wide at the top rail (measuring inside) and the rear is 62 1/4 in. I was hoping to put a Roll n lock on it, but not sure if they have one that accomodates that amount of bed taper or how it would look. The 1500s were that way, but I don't know if it was as extreme. Can't find one around here to measure. Guess I will have to call Roll n lock tomorrow.