Anyome change out a 2 piece front bumper like the 98-2000 to a 1 piece like the later 02-04 type? if so are they a bolt on swap? or no dice, brackets and all differ?

Most likely the brackets are going to be similar. But if not get new brackets. They are cheep.

on my 04 the bumper is held on with 4 bolts. not sure how that compare to one with a 2 piece bumper.

It looks like the cover on the one piece, just sets over top of the metal bumper. Part numbers call for the same bumper, for all 98-2004.
Anyone delt with replacement of this. The newer style should eliminate the problem of the exposed bumper rust/finish problems these trucks tend to have. Must be why Dodge changed it over.
I thought sure someone would have done the mod!

I want to think I remember someone buying a bumper off a member on here and his old bumper was the 2 piece and the one he bought was 1 piece I think he said all he had to do was flip the brackets and I think that was it but I cant be positive

Well I think Im going to try it anyway. Im going to get one off eBay, that way I dont think I will have to remove my front bumper at all. Just remove the lower part. And place the new cover over the upper metal part. That way I dont have to deal with removing the rusty bolts and dealing with rust on a new bumper in the future.
I will update if this works or not.
Heck they are only $90.