Does an extracted tooth blood clot have a scab?

No: Blood clots in an extraction socket remain soft and resorb as the wound closes. Bleeding from an external wound dries and forms a scab, protecting the skin as it heals.

Yes: The clot does have a fibrin coating ( principal component of a "scab") but it is thinner and often white in color because your mouth is wet. Think of how a scab on your scin looks after swimming.