Jonathan.. they had the gyra light, most videos as the one I linked to above have the mars or gyra light... I remember seeing them live on The National Limited, San Francisco Zephyr and numerous others. In my youth my family traveled and camped a lot. I kept a map and an Amtrak national schedule with me in the car from 8 yrs old onward. My Father would happily stop in endless towns where I knew a train was due. The 3 hour wait at Muncie for the James Witcomb Riley tested his patience but the payoff was E8 power a dome and an obs car! My witness accounts may not sway your view, but this Video evidence is proof. Present these for your perusal:
Again: https://youtu.be/NbIC6Iq2wB0
And : https://youtu.be/o7GZsE_T_ks (skip ahead to about 15:00 and later for SDP40F gyra light action in this video)