The last freewheel I took apart it was bone dry, no trace of dry grease or any oil at all, and it was an old NOS Shimano circa 1975. I would not be surprised if yours came without grease. I'd oil it with good motor oil, in one side and spin it constantly til it drips out the other. If it drips out dirty keep going til it's clean. Taking them apart is not difficult if you're mechanically inclined but do it on a bench over a rag to catch the bearings, then count them. I grease mine with synthetic automotive wheel bearing grease. I haven't had any sprag engagement problems, but synthetic can work itself a bit thinner than dino-derived grease...