Gregg,
Turn key in a manner. The engine/trans/install must be billed from a third party to allow the "component vehicle" status. The MSO will have been signed over to the purchaser by the dealer. Yes, the dealer can, in some states, procure the registration. In others only the MSO (MCO, COV, whatever you wish to call it) can be surrendered to the DMV by the listed assignee (buyer).
I am sure there is a means to make everybody happy and comfortable in the selling/building/titleing process....what it is, I don't know!
Rick