Did the US make any 100 dollar bills during the 1940's?

Yes, bill production goes on regularly, but in the US the date shown on a bill is its "series" date, not the year it was printed.

Until 1974 a new series date was used only when there was a design change or other major update, so the same series date would be used for many years. The 1934 series of $100 bills went through five different printing subseries between that year and 1950 when the design was modified.