I’m not sure I quite follow your question.
If you mean can you create file bookmarks directly in Scriptable and then use them in Scriptable from Shortcuts, then the answer would be no. That’s as per the on page documentation.
If you mean can you create a file bookmark from Scriptable in Shortcuts in one shortcut, and then use that later in another Scriptable in Shortcuts script, then yes. As long as it is listed in the Siri & Shortcuts section within Scriptable, you can access it universally from Shortcuts.
If you mean something else, can you please explain?