The pre-war hubs weren't dated with the month and year like the post-war bikes, but they did have a mark for the year, a single digit beside the "AW", I've seen "AW9" (1939) and "AW0" (1940). But some made around the war years weren't dated at all. In this thread, check posts #78, #356 and #309 for examples. I think
@GTs58 said the earliest post-war example he's seen with a date was from 1947. Sturmey-Archer may have halted production altogether during the war, but then again maybe not, depending on whether the British government saw enough need. I don't really know.