YFRR - Yellow Fluorescent, Red Ribs?

Yellow Fluorescent body with black spine, black eyes and red ribs. This color code is uncatalogued and the name is undocumented. This dates to the early 1970's based on the box style.

However, this same color is catalogued as YFO (Yellow Fluorescent, Red Ribs, Black Stripe OR Yellow Shad) from the mid 1970's to the early 1980's. There are some variations to this color for the Tadpolly Spook - one has a spine and eyes in the same color as the ribs, and the other just has the ribs but no spine or eye color. Whether they relate to this color code, YFO or have a completely different color code is not documented.

(Pictures courtesy of Andrew Girling!)