Yes bill, it would be using the new 3.0.0 extensions. Basically, just create your own ResourceBundle plugin and place it here:
/coldbox/system/extensions/plugins
That will make it override core plugins. You can also choose the location of the coldbox extensions by setting a new setting called: "ColdBoxExtensionsLocation" which should be a dot notation base path: "coldbox.system.extensions"
This works much like eclipse dropins features.
Hope this helps.