This is the old-style version of this pattern. I believe Blue Ribbon Flies now ties it with a Zelon wing and tail rather than the Krystal Flash. “Old” or not, this is one of my three favorite soft hackles (and four flies overall) on the Firehole in #14-16.
You are correct Walter…Below is their Green Version #16 with a Zelon Wing:
…and this is the original taken off the BRF site in July, 2009…
PT/TB