There is nothing wrong with that question, if you have never done it, then you have never done it.
It sounds like you have a firm grasp of the events going on in your joystick, so if you push it up (towards the screen) and it pushes the switch nearest to you, then yes, that switch needs to be wired to up, even if it is physically where you would think down would logically be, it sounds like the switch is below the pivot for your joystick, so do what you thought was right in the first place. If the bottom of the joystick was the pivot, then the switch nearest the screen would be pressed when pressing up, but from what you described, your joystick is "pivoting" in the middle, thereby crossing the movement.
Even if you did them all wrong, you could always override it with some setting changes in mame (you'd still need them to be electrically correct, but up,down,left,right, can be fixed I mean.(might be a hassle to your frontend though)).