I have a set of Branchline S.P. boxcars. They have roof walks, but I noticed that the info on the boxcars shows a build date of 1962. I thought that they had eliminated roofwalks and high mounted brake wheels in 1960. If so, I would expect to see older boxcars that hadn't been rebuilt to have roof walks, but not new construction built after the elimination of roofwalks. Am I remembering the wrong date for the elimination of roofwalks?