For GSS 2.5, when I run the first clone task (backup or restore) it updates the client, it's possible any task will update it.

If 2.0 has a remote client install that should work as well. Over all I don't worry about them anymore, as long as they do what I want, it's all good.

Try running a config refresh and see if that takes care of it, if not run a remote client install, then if that fails, image create task.

It I reinstall it won't that create a duplicate Client or will it just refresh my current client list?

For GSS 2.0 (i.e Ghost 11.0) I can not say for sure, but for GSS 2.5 (Ghost 11.5), if I remotly install over an older client, all it does is updates the needed files. The same thing happens if I run a task.

If you are worried about it, get a test computer and try it out. If you are correct, and it installs two clients, the worst you would have to do is uninstall a client from the computer.

However like I said, as long as the client still does what it is supposed to, does it matter?

For point of reference it does not create duplicate client entries in Ghost.