The 03-08 models have an adjustment at 600 miles and every 8000 after that. These models that I've adjusted for the first time (at 600 or 8000, sometimes 12,000) usually had one exhaust on the front tight and one intake on the rear loose. They ran much better after fixing this and didn't change much after, maybe one intake would be very slightly tight.
The 09-up have a different head with improved cooling, also better assembly, they have the first adjustment at 9000 and every 9k after. I've only randomly loosened up an exhaust valve on these on the first adjustment, they never seem to change after that.
The first adjustment at 8-10k is the most important and should not be skipped. I've worked on a few bikes that supposedly were taken care of at two other dealers in Seattle. There was no evidence the valve covers were ever off. If you buy a new bike, get some history on it yourself.
"Dad, can I get a motorcycle when I grow up?"
"Son, you can't do both"