Are you able to manually find the file in question via Explorer or command prompt?
I’m not entirely sure if this is what you’re looking for, but here’s one potential relevance expression:
modification time of file "bootmgr" of root folder of drive of system folder
This wouldn’t work on newer versions of Windows as the bootmgr approach has changed.
Again, it would help to have a better understanding of what exactly you are trying to achieve (for instance, what is the purpose of identifying the timestamp of the given file?).