Yes. As an former soldier, that is exactly what they do. Your rifle is your life. They were not lazy civilians who have ongoing debates to justify poor excuses and procrastination for not doing things properly. The fact that so many these old rifle are in such pristine condition is proof of the way they were maintained.
The part that is pretty far fetched is the ignorance of people today who doubt what burdens and sacrifices were made by our Fathers, Grandfathers, and Uncles, so we can enjoy the freedom and education that we have today. Well... some the education is not equal, but freedom nevertheless.
Illiterate and uneducated peasant soldiers could clean these rifles properly everyday, and did.