FWIW, the last two Shimano bottom brackets I bought (UN-54's), came significantly oiled in the packaging. The oil felt a lot like low viscosity motor oil. I assume it was done at least for corrosion resistance during storage and possibly for installation as well. I left the oil on when I installed the cranks.

I only mention this because I had previously bought two other square taper Shimano bottom brackets and neither of them came oiled, though they were a lower end model.