Yes. Debris within an oil system is sign either of a component failed and breaking down, or high wear. The top of each pedestal can be removed to carry out a basic visual inspection of the bearings. It is worth analysing the particles to establish the material being deposited, but preparations needs to be made for either a line shaft bearing change or tail shaft withdrawal. Line shaft bearing shells can be re-metalled and replaced in service, but most stern tube bearings will require dry dock and shaft removal to change.