Auto body repair & detailing: A hole in my 2006 Nissan Altima rear bumper., 2006 nissan altima, nissan parts department

Question
No excuses here, I reversed into my grandma's car. She had no damage, but I got 2 nice bolt holes from her license plate in my rear bumper.  I can get a painted bumper for a '02-'06 Nissan Altima, what I was wondering is: Will a '02-'06 bumper match my 2006 car (as in the same exact dimensions all 4 years) and changing a rear bumper, it is as easy as it sort of looks?  Undoing some screws/bolts and taking the old bumper off and then just replacing the new bumper in the same sort of way by just placing and screwing it in.  Or does there need to be welding, or any sort of complicated workmanship involved? Thanks for your input.  

Answer
Its not too diffficult, but I think it's worth it to pay the 75 or 100 bucks to have it installed. you are not used to dealikng with painted parts, and bumbers are easily scratched. i don't know about the parts cross reference on the years, you need to contact your Nissan parts department  for that info. Where are you going to get a painted bumper? You can't buy a pre-painted new bumper, and it may be difficult to find a used one the right color. Bill