If you look at the number zero on this keyboard you can see that it has a diagonal slash through it. I looked at the type slugs and my hunch was correct, this machine was manufactured for the military during WWII.
This kind of typewriter is known as a mill. Each of its keys types only in capital letters so as to be easy to read. The number zero has a slash through it so it would not be confused with the letter "O."
Looking up its serial number in the Typewriter Database, I believe this Corona was made in 1943, a time when typewriters were only available to the military. Civilian production had stopped and would not pick up until after the war.
Believe it or not, I passed on this beauty. I already have a mill from 1942 which was made for the US Navy. So, there it sits at Sweeten Creek Antiques in Asheville, NC for anyone who wants to make the trip and pay just $75.