As of CC 2020, the
uuid string key (a unique object identifier) has been added to the Adobe Illustrator object model. It is readable and can be used to retrieve a specific object in a script using the
getPageItemFromUuid() method. For example, if you know the object identifier, you can move it:
var obj = app.activeDocument.getPageItemFromUuid(439);
When you create an object, it gets a temporary uuid that is valid until you close the saved document. When you close it, the object’s new uuid is written to the file.
If the script saves the object uuid to the preferences file for further work, you should save and reopen the document before running the script so that the object uuid is fixed. Otherwise, at best you will save a useless temporary identifier, at worst the script will not work and an error will occur.