Bumper will fit if it's the complete bumper. All 98+ bumpers will bolt onto any 98+ truck, so long it's the entire bumper assy(metal, valence, cover, brackets, etc).
Only way you'll fit the grille is if you get a 04+ header panel, 04+ hood, and of course the grille. You can still use your stock bumper with the 04+ conversion.....but NOT your stock hood.