Found two shims , cant see where they came from!

[simsport]

I have taken the left side cover off to repair my starter clutch and was doing something next to the bike when I saw two small round shims about 1"dia with about 3/4" bore.
I hade taken the idle pulley and shaft out and the only place I can think the shims came from is between the pulley and crank case (as against pulley and cover).
Anyone recognise these shims and am I correct?

Thanks
Simon
PS I found the main crank nut was loose, in fact the tab washer had not been bent to lock it!!

[Lucky]

I haven't seen the starter gear shimmed, unless someone did it in the past..  i can't think of any other large shims like that on that side..