As others have noted, the standard Glock does not have a 2-1/2 - 3-1/2 lb trigger pull. The standard is 5.5 lbs for typical duty weapons.
Competition models have lower trigger pulls (4-1/2 lb), and mine is even lower. But, they aren't intended to be used as duty weapons.
I was trying to illustrate a general point of theory. That should have been clear from a subesequent post where I mention specifically GLOCK trigger pulls.