2012 under glovebox panels?
 

there are 2 panels under the box that meet & one overlaps the other at the ends, This is really stupid because they bang against one another. Currently I put padding between. Is this right or do they fasten somehow?

The panels may have a round spacer to obtain spacing, or perhaps the panel fit is such they overlapped when should not.

There have been various complaints about glove box rattles from lack of spacers and the key lock. Suggest if problem is not obvious (missing part) to take the easiest route which you did, perhaps gluing the padding in place. Or perhaps drill a hole in the panels and install a screw.

Not the best answer but the dealer most likely will not be of much help and might even do the same thing.

At least you were able to easily find the source of the rattle and quiet it, which is better then other owners.