I tweeted at Park Tool for some help and they were a little bewildered because they said
Interesting, The notched lockring is not normally found there. If someone has installed that in the past they may just be using it as a spacer. If it is indeed threaded onto the steering column then you will need a hook spanner like the HCW-5 as well as the HCW-15.
But it seems perfectly normal to a lot of y'all and people in C&V as well...