Presumably because a RH threaded fixed-cup has a tendency to loosen in use, my mid-60's Peugeot has punch marks on BB-shell to secure cup. Don't know if anyone else has seen this...also don't know if this was factory or subsequent.
In some cases, I have been able to tell fixed-cup direction by looking at the last few lines of thread inside the BB shell in strong light. This came in handy in my recent fix of Paramount that someone had reversed installation of cups!..???
Jack Romans
Sacramento, CA