"O.S.S. was a Buckeye Productions and Associated Television co-produced wartime television drama series. It ran for 26 half-hour monochrome episodes during the 1957–1958 season and was distributed by ITC Entertainment and networked in the United States by ABC. The series followed the adventures of Frank Hawthorne, an agent with the American Office of Strategic Services, who operated behind Nazi lines in occupied France." This is another show that I can't find anything on but what I did find was a snip-it of its intro and beginning of one of its episodes. Take a gander below to see what it would have been like.
Sorry I couldn't find more,