No it doesn't, so I guess the restrictor plate wouldn't be useful for q-bert after all. But, given how the universal mounts (basically just like a push-button), you could easily loosen the push-buttonish nut holding it to the panel, rotate the entire joystick 45 degrees, then tighten it again. With the restrictor plate set to 4-way, that'd give you perfect q-bert play.
They're nice sticks, both with regards to feel and versatility, but don't look all that much like traditional arcade joysticks. Their main eyesore is the large square plastic base which is visible above the control panel.