In the end of The Return of the King:
Time went on, and 1421 came in. Frodo was ill again in March, but with a great effort he concealed it, for Sam had other things to think about. The first of Sam and Rosie’s children was born on the twenty-fifth of March, a date that Sam noted.
Sam... noted this date?! Isn't that an absolute given? Who has such a major life event without even "noting" it?
Does "noted" refer to something else, like many words have an original/archaic meaning in this book?