Well I finally found someone on RGV that put the HD2500 hood on the 1500 without doing the complete front end swap. As you can see it does bolt up, but overhangs the grille quite a bit....I dunno
Not including the cap, there is a height difference between the the two grills. Easiest way to think of it is that GM used taller bumper end caps and the taller grill to kind of overlap, and hide the taller HD frame. Most parts will switch back and forth(expcept grills), but not using all of one type of front end will leave you either making custom pieces or having things be off by at least a little bit.that's why you have to get the cap for the grille also.