I'm sure MJ had the song in his mind while he was making SC due to the similarities both songs have, he even specifically says "Chicago 1945" while talking about SC in his Home Movies documentary.
I think about that with a lot of the songs the Estate has released or considered releasing, would we have heard them if MJ was still alive? C1945 is a bit likely since he worked on it for 20 years up until his death, so there's a chance he was going to use the song eventually. But what about the songs that MJ forgot about or didn't work on them for decades? Would we have gotten I'm So Blue, Dream Away, Behind The Mask, This Is It, Who Do You Know, Al Capone, Price Of Fame, etc. It makes me wonder.