If any of ya'll in this here Forum has changed out the front end clip, that is the hood, fenders, grille. and bumper, of a '00 Silverado for the front-end clip from a '02-'06 Silverado how did that project go? I reckon it to be more than a simple bolt-up project such as a new radiator support and miscellaneous brackets. Oh yeah, in case it matters the truck is 2wd.
I seem to recall @donyms replaced some of the front end fascia on his 2002 Silvy with Tahoe fascia from a 2005. I don't know how much parity that might have with what you're up to...
I'd expect it to be a fairly simply bolt up project. If you look in my Albums you'll find one with all of the front fascia (bumper, grille, valence) removed. It takes maybe 10 mins to take that stuff off and the oil cooler (if present), condenser, and radiator are all left in place, unmolested. The hood on my Sierra is 3 bolts per side, which is simple enough. I can't speak to the fenders as I've never had mine off. I also can't speak to the parts interchangeability between the years you've mentioned.
they are all simple bolt on. i helped my friend with his 05 duramax with a escalade front clip. all fit and everything from 99-07 silverado body styles (silverado, sierra, tahoe, escalade, suburban) will bolt right on to everything as long as you have all the peices.