I don't have any S&Ws with the lock, so I haven't really followed this topic, but I do have two questions. Why did S&W come up with such a complicated lock system? I have a couple of Taurus guns with locks, and it seems to me their little pop-up lock at the base of the hammer is a lot less complicated and really solid, reliable, and foolproof. The other question is has there ever been any noise from ATF about folks removing the lock on their S&Ws? I'm thinking of shades of bump stocks and AR pistol braces.
Your question(s) are good; however, it's a bit off-topic in relation to the original poster's question.
As for the S&W Internal Lock System ... I think there is an article that may pique your curiosity ...
revolverguy.com
Article: The History and Future of the Smith & Wesson Internal Lock