Bates & Richards "Fishing Atlantic Salmon - The Flies and the Patterns", page 343, specifies "peach" as the color of the colar hackle. However, the photo on in Plate 140 page 332 appears to show a yellow-colored hackle.
You know, I thought to look online for your pattern and only got historical stuff about Bing Crosby Specials. This gave me food for thought. Did you ever notice how the camera makes celebrities look younger/older than they really are? Well, you might consider this fact and go with the peach over the yellow. That's the best that I can do. :dunno