In the sigma series there is actually a spring that the only job it does is increase the trigger pull. All they do is remove/replace that spring and presto you shave off 3 or 4 pounds of trigger pull. I have heard that some PD require a very hard trigger pull (upwards of 10-12 pounds) is the reason S&W gave the sigma such a ridiculous "need a winch line to help you pull" trigger.
If it affects the way you shoot then get the trigger worked on. If it doesn't then I wouldn't worry about it.
Oh and welcome to the forum