I won't say never, but milk/cream and sugar wouldn't have been available often in the field. I know from my (20th Century) Army service that strong, black coffee is still the beverage of choice. (In one office in Europe near Stuttgart where I worked for a time, the usual office staff was a major and a sergeant-first-class; they would start the coffee going in the morning and just add new coffee through the day, never removing the old grounds. By the evening, it was something fierce.)
I drink black coffee on a regular basis, though I don't mind the occasional latte or something to change things up.