........does it matter?
(1989 Ninety)

With a 1989 model that is how it should be. The gear oil is shared from the diff like the series landys.
If you are changing say a hub seal then a smear of grease on the bearings to keep them happy until more oil migrates from the diff [keep diff topped if you have had an oil leak.]
A better system in my mind than the later sealed axle/grease hub system of later models. Some even convert newer models to the old oil system.