Yes they do, the slab side are put on dry. That keeps them from moving. Grease is put on the blade side. If you keep track of which side is against the slab, you’ll have wear against the blade only and with time, the knife will become smoother.
With the older solid washers it makes a difference. It’s more of a habit with the newer washers. On the older washers you can see the wear pattern on the blade side. Really don’t know if the newer washers with the grease pockets make a big difference if you don’t pay attention to which side is on the slab side. For me, it’s more of a habit since I’ve got some with the solid washers.