We found a few Royal typewriters on the internet that have U.S. Navy etched onto them. At the beginning of the war, the War Dept. grabbed up every typewriter that they could find for sale. Ships and shore installations that didn't get issued one had someone go to the local shops to buy one. It sounds like Royal had portable type writer contracts with the Navy, but the Army used whatever they could find. A lot of the typewriter manufacturers went to making other items, like weapons -i.e. Underwood. We have an Underwood in our Yeoman's "shack".
A BLHA member posted pics of all 3 type writers on our Yahoo page and the two in the radio shack are a Royal and an L.C. Smith & Bros., which is pre-war.