Changing your membership is one thing but ownership is another, DVC it a deeded property just like a house. You need to decide who owns it and correct the deed if necessary.
You do not need to have the deed changed until you decide to sell or otherwise transfer the property. You just need to have MS do the member name change in its file if you want to use your new last name when dealing with MS and reservations.
We've seen reports of them doing this on paper but not legally and we've seen reports of them requiring you to change the deed. Let us know how it goes for you please. I wouldn't spend money to do this unless you want to add others to the listing as it seems you don't.
You might check to see if you can file a "same name as" affidavit. That would get your deed name change out of the way and it might make life easier when you sell.