When you create a sequence script, it is available only to the associated asset.
If you want a script that will be available for later reuse, for registration on other assets of the same model and for configuration in a Run Script action for a rule, you need to import the script from the Script wizard. When you save the imported script, it is immediately registered on the related asset. In addition, when saving the script from the Service application, you can select to publish it: from the Configuration application, the script is published automatically.
Only after a script has been imported and published from the Service application, can it be registered on other assets of the same model.
Scripts cannot be un-published. Your option is to delete the script from the related assets, by unregistering each: you can do this from the Configuration application, Manage script registrations page.
Scripts installed on assets are available for running and trigger-action configuration on that asset only. You cannot publish these scripts for use on other assets, but you can perform a Run Script action on these scripts.