If you use the license plate insert nuts, I think the threads will be sheet metal type. At least that's what my license plate screws are. The 1/2-20 screws might thread in, but might not. You can get oval head sheet metal screws if you need to.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.