I believe your friend is talking about the practice in the late 1930s of marking some M1903 parts with a drawing number, like you see on M1 Garands. A good example is the handguard made in the late 1930s - it had a D28179 stamp on the top. While such parts were used on National Match M1903s, they are also seen on regular service rifles of that period.
"We make men without chests and expect from them virtue and enterprise. We laugh at honor and are shocked to find traitors in our midst."
--C.S. Lewis