Fid's information, interestingly enough match (location) with the Kaiser and Frazer antennas 200003 and 200004 (standard length and longer length versions). The illustration shows the "factory" antenna type. There are pictures of K-F products with antennas installed on the SIDE of the fender like Willys Station Wagons of the late 1940's. Some dealers used non-factory assemblies so the antennas came up anywhere.
Based on the assembly instruction sheet, factory installs would be on the left side because that's what their instructions say. However, I would guess that running the antenna wire would be easier off the right side because you would not have to navigate the mass of wiring and the speedo cable run that you find on the left side behind the dash.