Check if a file is opened as Rewrite or Append

In Delphi (10.3) is there a way to test if a text file was opened via Rewrite or via Append?
I've found this: Checking File is Open in Delphi but it doesn't help as it only says if file is opened for Read or Write.
Note that I can use a global Boolean, initialized to True if I open the file as Append, and to False if Rewrite, but I'm curious to know if the is another way.