The only difference (I think) is the white plastic actuator on the base of the shaftThe actuator makes contact with the microswitches, the eight ways are a square shape, and I think the four ways are round.
It depends on which of happs joystick models you are using. The super has a black round actuator with one end bigger than the other. If the larger end is down, it's an 8-way, if the smaller end is down, it's the 4-way position. I'm not sure about the other models 4-way vs 8-way, except the competition 8-way has a white square actuator.
The best way to check is to look at the bottom of the joystick while you move the stick on top. If two switches are pressed at the same time when the joystick is in a diagonal, it's probably in the 8-way position. I saw probably because the 4-way position is not a true 4-way joystick, and sometimes both switches are pressed anyway. If they click at basically same time (on to on, one to off), or there is an space where neither are pressed, then it's setup as a 4-way.