When the PDF is opened will:
1. Ascertain the current Overprint Preview setting and note it.
2. Set Overprint Preview to "Always" (if it's not already).
When the PDF is closed will:
1. Restore the previous Overprint Preview setting noted in #1 above.
Is this possible?
Apologies for the confusion but I was referring to the Acrobat Page Display preference setting called "Use Overprint Preview".
It's good to have specific information, you know, so we know what you're talking about.
But the answer is still No, Very few of the preference settings are available though the JS DOM.
Best option is to use a PDF/x standard like PDF/x-1a or PDF/x-4. But hard to get fool proof for customers.
An alternative is to give a screen version sRGB with simulated overprints… that will work on any device with any PDF viewer and what I used with non save clients.