This doesn't indicate that the timezone is actually stored along with the timestamp. In fact, looking at the
file format specification, there are only 4 bytes allocated to the file time (FTIME).
As far as I can tell, the timestamp, adjusted for the system's local time, would be stored, but not the timezone offset itself (let alone a DST flag). This is pretty crucial information if you want to know,
accurately, the time that a timestamp represents (I've had to "deal with" "non-local local time" as part of my job). You would need to already know at what time the file was created or modified in order to make any educated guesses about the timezone offset.