The only acting credit for legendary jazz singer Anita O'Day (Sheila Mangan). Ms. O'Day died at the age of eighty-seven in 2006.
By the stripes on his U.S. Marine uniform, Paul is a sergeant. He is wearing ribbons for the Purple Heart, Marine Good Conduct, and National Defense Service medals on the first row. On the second are ribbons for the Korean Service Medal (with 3 campaign stars), UN Service Medal for Korea, and the Republic of Korea Presidential Unit Citation.
The helicopter at the end of the film is a Bell 47G-3B, registration N1136W, which was canceled in 2018. This aircraft can also be seen in Espions en hélicoptère (1968).
Charlene Holt and Robert Donner had co-starred in Howard Hawks' "El Dorado" three years earlier, but in neither film do they have any scenes together.