Mike Trent makes some good points, albeit with toung in cheek.
I am wondering of this could have been a possible scenario.
On final day, #60 brings the drain from Denver to Como. At Como #9 is switched to the head end and takes the train to Leadville, and then the entire return trip from Leadville to Denver.
I'm wondering if some guys in the Como shops could have cut a special metal #(9) and attached it to the cab, to mark this historic occasion. Last run, very special occasion. Removed when it returned to Denver. Shop guys love to do this kind of stuff.It's there way of marking an occasion...with their own special contribution.
In the Helen McGraw Tatem film, it is pretty obvious that when train 71 west, stopped atop Boreas pass and passengers got off for a minute, that this was the time Tatem made the film CU of the "9" on the side of the cab.
This makes much more sense to me that any other idea. Certainly a SS sheet, cut to "9" was never seen before or since, in photos of the engine...yet it seems to be there on the final run.
Any thoughs, Mike Trent?