[Suicide Junkie]

What you could do, is run a DOS shell command:
dir "filename.gam" > test.txt

Then, open test.txt, and see if anything has changed since you Last opened it. (compare with a backup copy of test.txt, made just before you ran SE4 Last time)
This will be sensitive to file SIZE, and creation TIME.

If anything has changed, then SE4 must be done, so run the next turn!