For the most part, I agree that a 642 doesn't really need extensive work. One certainly doesn't need a light trigger to be effective.
Having said that, a smooth trigger pull can be beneficial and may be worth the cost if your gun's trigger pull is less than optimal. I've often considered having a trigger job done (with factory springs retained for reliability) on my 642-1 as there is an occasional hitch towards the end of the trigger pull. It doesn't affect reliability or accuracy (as far as I can tell), but I would prefer a smoother, more consistent pull. I have a 642ND with a trigger job, and it is a noticeable improvement. I've also considered having the front sight re-profiled to more of a modified ramp/Patridge shape as the full ramp profile is prone to glare issues in some lighting.
Personally, I don't see a problem with having work done on your carry gun, so long as reliability and safety aren't compromised. But I think you may be better off seeking a good gunsmith in your area who can perform the work, if possible. You won't incur shipping expenses, which can be a significant portion of the total cost. The price of the work itself may be less expensive. Turnaround time may be faster. I don't know what C&S's turnaround time is, but it's not unusual for well-known gunsmiths to have turnaround times measured in months, if not years. I've had trigger jobs done by local gunsmiths that turned out nicely and took, at most, a few weeks. And if there is some kind of issue, it's much easier to deal with a local gunsmith than having to ship the gun (again!) back to the gunsmith.
Just my opinion.
