I believe the last ECM flash TSB was February 2005, so cars produced after that time probably don't need the campaign.
The notices say to check with the dealer to see IF you need the work done as a dealer may already have done the work based on TSBs. If you got the notice, you are probably going to have the work needed.
I had mine done Saturday, along with my oil change schedule. Mileage appeared to drop 1+ MPG but pulled back up with my usual commute. The drop in MPG was probably more environmental, and possibly a slight loss as the trims re-adjusted.