The front sight on the Glocks that I've owned have been fixed, non-adjustable. The rear sights are adjustable, though.
Originally Posted by dks7895
Adjust the rear sight to change point of impact.
In other words: if your shots are hitting right of your point of aim, move the rear sight to the left. If you are confident about working on your own guns, use a small punch or a sight pusher, moving a little at a time & test-firing to check your progress.