No, I think the pin Casimer is referring to is the one in the trigger that holds the "mousetrap" hand spring in the older S&W's. It is a single wrap spring; one end rests on the stud in the hand and the other in the trigger. To remove the spring, you have to remove the small pin that holds it. As I said, there is no reason to remove the spring unless it weakens or breaks, both very unlikely conditions.
In the latest revision, the hole and the pin are gone, and the spring sits in a hole in the trigger. That method is as good as the other and a lot less expensive to make and assemble, but it would probably not be possible without using MIM for the trigger.