In 1941 the 1924 Landlord’s Game patent expired so it was dropped from the packaging. The games from this era are known as single 2nd patent games. The editions available at this time were the #6 (black and blue), #9, #11 Library edition (no picture at this time), and a new De Luxe edition #12 (no picture at this time) (I have not seen evidence of a #8 from this time period even though Parker Brothers says there was one -- if anyone has this game or has pictures of one please contact me). Other than dropping the earlier patent on the boxes the sets were basically unchanged in 1941.
1942-1945 was another story. WW2 created a metal shortage so a composite token was substituted in the #8 and #9 editions (the #8 I have with composite tokens is a dual patent with 2nd patent rules, so maybe an overage of dual patent #8 boxes were used during this period).
The #6 blue box retained its wooden tokens and the #6 black box received wooden tokens and the tokens were removed from the graphics on the box (I have seen a couple of these with composite tokens). These composite tokens are not as rare as thought as they were made for 3 years. The #11 and #12 seem to have been dropped.