Keep in mind that "Delete a pairing between remote and iPod dock" means your Apple Remote becomes universal Remote for any Apple devices with IR receiver. That includes most of the Macs, Apple TV, and iPod dock.
So whatever you do, it will always work with your Dock. Since it will only switch between "discrete remote for your Dock" or "universal Apple Remote which also works for your Dock, and any Apple devices".
But when the remote paired with your Dock, it won't work with anything else, only with your iPod dock. So to test whether your remote has been unpaired or not, test it to another Apple devices with IR receiver, if it works too, then it's been unpaired succesfully.
To pair it again to a specific Apple device, use [Next] button instead of [Previous] button from GGJStudios' post.