I've only had 1 Smith that needed warranty work, and that was over 20 years ago during the "Bangor Punta" days where QC was "varied". It was a problem that I would now fix myself. The only 2 other Smiths I've had to open up and work on were made in 1926 and 1954 respectively. Less than two hours total and they both shoot like new.
Also, S&W's warranty department does a good job based reports I've heard from folks who know.
I wouldn't worry.
I won't now. Thanks.