Yes, the passenger cars stayed at heir original terminals. Engines worked end to end and returned.
Your off by one day...
The train with 497 helping 487 was on Sunday, September 22. However, 497 did not go through to Antonito, I ran it on to Osier to relieve bad ordered westbound 488, and bring #3 back. It was the only day 497 got east of Cumbres until maybe the 25th (eastbound) and 26th (westbound). Chances are pretty good that is 497 with yours truly (and Mark Yates firing) making a smokey departure from Los Pinos Tank.