Argo,
Colonel Roseman was Army in the Vietnam era. Served at the very end of the second world war in the Marines, after graduating with a chemical engineering degree. Had a full ride football scholarship. After discharge, he joined the National Guard, and was activated during Korea, and decided to make his career in the Army. Made his mark in guided missle research, served at the Army College in Saigon during the Vietnam war. Retired as a Colonel.
Was an interesting man, and left us in 2007.
Having said all that, his editors at The Rifleman may very well have editied out any comments regarding his service that he had in his article. It was a short article of two pages, and editors are notorious for leaving what they consider unimportant to the story, out.

Best,
Ted