Why even sign a memo to yourself? A date: certainly, but sign it? I have never signed a memo to myself, maybe I should start.
"Why even sign a memo to yourself? "
a formal MFR, I can see signed; in case you have to use it to document something later on, you can show it to your boss, e.g., and it has the date and your signature on it to show that it was contemporaneous with the event.
the signed, dated MFR just gives you more credibility that, yes, you realized it was a serious matter at the time, and took the time to record it for future reference, should it be needed.
a note to yourself for your own recollection: a date, yes. Why sign or initial it? Don't know -- other than to verify to yourself later, when you no longer remember having written it, that, yes, I did write this. You wouldn't need a signature block, esp. an unofficial one.
Yes, this stuff is curiouser and curiouser if you try to come up with a believable scenario. I originally left open the possibility that the commander wrote these notes to himself, and were informal and he did not take the time to follow memo format, etc., because it was just to himself. BUT the widow's testimony that he did not type --- which I believe -- knocked out that provisional support.