That SD9 was only ten years old at the time and the stripe color would have been Duco Orange, aka Grande Gold.
It is interesting that the yellow stripes on the black hood units had two shades of yellow/grande gold. In my Rio Grande in Color Vol 1, I could be wrong but it looks like the SD7 5300 on page 52 and GP7 #5100 on page 52 has a darker shade it appears. I used to think it was just the lighting in the photo but I recall folks pointing out that some of the hood units received a different shade of yellow midway through their production/painting from the builder.
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