Not sure exactly what you are referring to, but if you could post a pic it would help identify what, if anything, needs to go where..
If you are talking about the BULBS, then yes there should be a washer/grommet that goes between the assembly and the bulb where it attaches to the assembly...this is to prevent any water or moisture from getting inside the glass part....
If you are talking about the headlight assemblies themselves, when I replaced them on my '011 EL, there are just 2 bolts on the top that screw into & secure them to the frame, and 1 round "post" that sticks out from the bottom area, which when pushed on, pops into one of those self-grabbing socket thingies and boom, all done
There is also a small screw-looking thing that is used to aim/adjust the headlights, but that one has a nylon washer behind the head and a lock washer on the other end, and has nothing to do with the mounting parts....