Center trim for 2 axis Joystick?

The product documentation for the 2-Axis Joystick does not mention anything about a trim for centering the joysticks, and the feature is not present on any of the several different mini joysticks that I have.
This page clearly shows such a feature to exist. Is it really true?
This page clearly shows such a feature to exist. Is it really true?
Comments
-- Gordon