OK so am going thru the new to me 5ver since being used you don't really know,Its my 1st trailer of any size anyways and the first with brakes, My sprinter has two axles and while I was packing bearin...
Being your packing the bearings, why not take a hub down somewhere and get what you might need in case of repair on road. You'll also find out exactly what axle you have so you can look up right manual.
I carry a spare set of bearings, oil seal. Many with the "never lube" carry the whole hub.