After a pack and go, the first time you open the filenames, the filenames are still those of the old assembly, you just need to rebuild the assembly and the new filenames appear.
Beware of external references and related equations. These two elements are not always well re-fenced with Pack&Go. Opening your assembly in "Resolved" mode associated with a reconstruction (CTRL+Q) should resolve the Component Names visualized in your Build Tree... Kind regards.
During the PACK&GO, don't forget to "search/replace" for the parts specific to the project (excluding commercial parts)
And also give a new folder (by the way all the pieces will end up in bulk and moderately satisfied with the "keep the structure of the folders" function)
See also my question and answer for the time being, on the names that didn't change once in SW (Ice in SW to be done once).