I'll be interested too. I could not find a place for the big metal "shim" either. Nothing like that came out of the old one.
Just because you didn't remove a part when you dissembled it doesn't mean you don't need it
Previous owners are notorious for screwing things up

The large diameter shim in the kit is critical in some applications
If your engine requires it and you leave it out you can have loss of oil pressure and destroy your engine
I do not know the cut off dates of when it is and isn't required
But a simple search of the "2000 dollar O ring" will tell you all about it
But the best info is here at Snowbums tech articles
http://bmwmotorcycletech.info/technical-articles-list.htmAfter you are there scroll down to the Mechanical section and then to Line 51a
Every Airhead owner should be aware of the issue with properly installing an oil filter