You mean this one?

No. That's the Nixon-era one, as you noted. Subsequent Presidents have issued their own variations on it. I think the most recent one was the Obama-era one, since I don't believe that Trump issued a replacement one - so this would be it:

obamawhitehouse.archives.gov - Executive order classified national security information

Hmm. Wonder if that's the case.

Perhaps not, though the article you linked isn't really relevant to that point. Something doesn't necessarily need to be classified in order to remain governmental property and a Presidential record (like the notes from Kim Jong Un). Certain governmental records are the subject of criminal statutes (like the one I linked to upthread). Other governmental records are simply the property of the government, not the President as an individual, and are required to remain with the government even though they are not classified.

The cocktail napkin and birthday dinner menu are certainly not among them - they were almost certain taken simply because they were in the same box as other materials that were properly seized (and were likely given back to the President, assuming he asked for them).

None of that affects his liability for the records that he did take and retain even though they were either classified or related to national defense.