A door lock chassis has a gauge insert that defines different dimensions corresponding to different door thicknesses. The gauge insert is positionable in the lock chassis in different orientations corresponding to the different dimensions used to align the lock chassis for different door thicknesses. Additionally, a door lock may include an anti-rotation assembly for preventing rotation of the lock chassis. The anti-rotation assembly may include a retention member that is secured to an inside hub of a lock chassis. As an anti-rotation member is displaced in a first axial direction along the inside hub to a mount position, the anti-rotational member may deflect resilient members of the retention member. With the anti-rotation member at the mounted position, the anti-rotation member may be in a frictional engagement with the previously deflected resilient members so that anti-rotation member is retained at the mount position.