s1214 wrote:
Be careful with your definition of 'dimensions'. I went from a 2002 GMC to a 2011 GMC. The chart shows the same dimensions for both but I can tell you the tailgate opening is different. The 2011 has radiused corners calling for a 1 1/2 inch riser to clear it.
Right! You need to investigate what years the body style changes. Dimensions don't tell the story.
Even in the old days, 1987 and earlier, before any of the Big Three started tapering the truck boxes narrower at the rear, dimensions were standard and canopies would physically fit all three, but the back of a Ford cab angled forward, Chevys were more vertical. You still needed the correct one for it to look right.