This cartoon not only has the movie connection with the billboard spoofing Mrs. Miniver (1942), but it also references itself. The billboard also advertises the added M-G-M cartoon "The Early Bird Dood It! " with a poster similar to this cartoon's title card. And, the Worm comments he hopes that cartoon is funnier than this one.
The bird uses a Worm Ration Card - the earliest ration card for World War II was issued in May of 1942.
The cat holds up a sign commenting on the film's sad ending, which is true. Most cartoons of the golden age of animation had happy, or at least silly, endings. This short was decidedly a bit adult in its humor, from the shapely leg gag to the bar beer break, however, so a sad ending would not have been entirely unexpected.