Yes, that process should work just fine for renaming a project.
Just remember that there is, then, no corresponding project in Paratext 7, so there is no way to re-do the migration and get the same project as a result (i.e. every time Convert Project is used, it will create a new project with a different internal ID). This means, even if you re-converted to the same project name, none of the Paratext servers would “see” it as the same project as the original conversion.
Most of the time, this shouldn’t be an issue, but if you are planning on pre-registering the project before a final migration or something like that, it wouldn’t work.