In the trade for about 1/2 of that 35, and I too remember it the same way, but have noticed that it is no longer the case. I'm sure it was a requirement at some point, but can't tell you when it was removed - But I think "Line" was stamped at the top for everything for quite some time after that. "line on top" - is something that I was always told....
Or, maybe the last vestages of any wording that may have implied it are in 404.6(A-C)
"Single-throw knife switches shall be placed so that gravity will not tend to close them." And, by design... it ended up that way - 'Line on top'.
