As a slurred out before , Mass production cars have this minor problem some times , the dies and presses and the production plant ware out and , they do not quite fit , its an Xd and i dont think (QA )was such a big deal back then , just a matter of getting the thing out the door. so to speak.
When was young and silly in the trade, you would see brand new Eas thro au fords and the like with the most averge body panel gaps.
of cos now days every ones out there to prove there manufacturing abilty...
I had an Xe uterus for a time and it was so bad for rust that a tentus shot was advised after use,
Lower bottoms of doors and sill panels as well as Q panels ,, back edge of doors espeacily would rott out no worries ,,,
To this day i am still amzaed at when FMOC bought out the XH range , unreal... ,, dont get me wrong i love em .. but with all the old style body problems will emerge after time ,
Ive seen brand new , not new , new but couple of kays on them , get rust marks in the inner skirt , where its welded to the bulk head ,, just body flex , base sealer on the commceial production line .
id recken in all fair ness your lucky to be even driven around in an XD , cos there ait that many round , iether way it can not be that bad ,