I'm inspired by our fine weather to finally install my  Race tech fork springs.  Recalling the last time I opened those up, I struggled mightily with the lock ring BMW #31 42 2 312 919.  That is exactly the sort of thing that tries to escape my grasp and spring to the darkest, most inaccessible corner of the work area. Better to have new in hand before I do the swap.  Turns out that there are reportedly zero (0) in north America.  Would those lock rings be available from local suppliers such as NAPA or bearing supply houses?  Does anyone know the dimensions of the rings?  
I'm trying to give this some forethought to avoid having the bike inoperable due to something as silly as me losing a tiny lock ring.  
Yes, Murphy is my constant workshop assistant.