*grumble* I hit "Edit" instead of "Quote" for this followup below, and the system went and overwrote my last posting instead of adding this as a new entry, so I'm trying again here:
Previously I wrote:
I don't have the book here with me but my guess is that it'* a mounting point for a corner of the panel where they didn't have room for a full-size clip, and the stud (which I assume was molded on the back of the plastic cladding, not on the door) would go through a hole in the door and be attached on the back side with a PAL nut...
Okay, I finally looked it up in the '93 manual, FWIW, and it shows six clips along the door and one screw (not a stud) at the back, going _outwards_ through the door panel into the back of the plastic piece. For some reason the instructions accompanying the diagram talk about removing two screws, although the diagram itself shows only one. It'* also not clear from the diagram whether they're illustrating an SE or an SSEi, and I forgot to look on my doors while rushing to the train station this morning.
So anyway, what you see as the end of a stud on your panel might actually be a mounting screw with the head broken off. See what the door on the opposite side looks like.
In any event, I think if you've got six good clips holding it on, it should be fine. The screw would be used to prevent the panel from shifting lengthwise on the door, and possibly snagging on clothing or on the edge of the front door.