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I really don't know. If I had the task I would compare the table structures and see if anything is different and whether or not I could get the data in the new tables.
This is where a test database is handy. You work on the tables until right and then drop them into the live db. You can start by comparing the two mysql.sql files. If they are not the same you might be able to work on it.
I didn't have a big need for downloads so I don't have it anymore. Are your old tables very large?