If anyone has a clue I would be deeply grateful-- my curiosity is tormenting me!
Oh, by the way, the notebook is a small Massbuch, a Catholic calendar, though if there is a connection I can't make it out.
Edit: The mystery is solved! A Twitter friend, @norlik, figured out that this is in fact a list of stamps-- Polish stamps. The gr is neither grams nor grains, but Groszy, 1/100 złoty.@norlik even found a link to one of the stamps mentioned, the Madame Curie commemorative.
Thank you so much, @norlik! I love the internet!