besides the 2 bed lengths, long or short
the widths may be different, between Generation 1, Gen 2, & Gen 3, i know that the Gen 4s have a strange curve at the top of the bed rails
I believe in the year 2002, there were 2 body styles, early July - December 2001 & late January to June 2002
Production year goes from July to June
Like the 2013 Rams will start being assembled next month, late July 2012
here are the 2005 Ram dimensions
pick your cab style first
then select DIMENSIONS
I think you will find that outside to outside bed rails are 79.6 " or 6' 6.3"
tailgate to front box panel is something like 76.9" or 6' 4.9"
i read that the bed length for the year 2000 1500 model was 6.5 feet, so that may possibly fit
i could not find the width at the top outside of the bed rails