It won't make one bit of difference if you enroll your Week in the DC. Enrollment does not change the deed of an existing Week one iota and when you sell your Week you will be selling exactly what you purchased. Enrollment of a Week does not transfer with the resale.
As well, any Weeks which are resold now on the external market* cannot be enrolled by the new owners, because resales purchased on or after 6/20/10 are not eligible for enrollment. (*Weeks which are resold through Marriott's Resale Operations may be eligible for enrollment, if the new owner purchases a DC Trust Points package at the same time.)