Well, aside from thinking you should (after downgrading to 2.0.5) upgrade that to 2.0.8, yes....
Assuming you have a 2.0+ database, you simply drop the database tables (not the db itself!), delete the entire fileset in the wp installation (EXCEPT for wp-config.php and any special/custom theme files), upload the older version fileset, and run install. Then once installed, go back into the database, drop all the tables (again, just the tables, not the db!), import the 2.0+ db backup, and visit the admin section. If you get an upgrade notice, click it....
Should be good to go....