I just got a nice vacuum-fill Sentinel and its matching pencil (I think 1948, as the dot is on the cap above the clip), and there's a funny extra mark on the pencil's impression. The impression itself runs belt-wise rather than length-wise, and in line with the "W.A." of the first line of the marking, but below the "Made in U.S.A." there is a very distinct "FA". I can't even begin to guess sensibly, as "FABRIQUE EN E.-U." seems unlikely. Anyone got an informed, or even quasi-informed, stab at it?