The difference between sheepskin and Lambskin is one that is often confused for the wrong reasons.
A Lamb is an unshorn sheep, where as a sheep is older than a lamb. Lambskin is the skin of an unshorn lamb, so is softer. This softness is desired in the use of floor mats, infant care underlays or baby underlays, pramliners.
On the other hand sheepskin is cheaper and better suited for medical under lays, bed underlays, etc.