Disabling Blogs and templates and their effect on users blogs


I have removed some old Templates that I previously had setup in my network install because I no longer want to offer those. I also want to disable the initial Blog for each of these. Can I do this if I have user that are using that template? I guess my question is, once a users blog is created based on a template, is it completely new and no longer relies on any of the original blogs or templates?

Thanks, Chris