Bolt/Nut for Grove Nosewheel

I have the Grove nosewheel for my RV-7A. Just had to change a leaking tube and noticed that the bolt and nut that secures the wheel to the gear is the undrilled -60 bolt and fiber locknut that was supplied with the Van's kit.

However, in looking at the Grove site, under the Installation Guidelines for Pre-load, it mentions a drilled bolt and castellated nut (neither of which I remember receiving with my nosewheel/bearings/axle.

I am awaiting a callback from Grove but, in the meantime, what is everybody else using here? Seems like the drilled setup would be a bit safer, yet DWG C-1 shows the undrilled setup and I can probably assume there are many RVs out there running just fine with this setup.

I used the Vans bolt, nut, washer setup but my Grove wheel went to Anti-Splat for the bearing mod so pre-load is not a concern, along with re-packing the bearings every year.