I believe the original had a painted cork body. And, yes, it's Bunyan, the reference being to Paul Bunyan the mythological giant lumberjack, because of the fly's size. Often thought to be a salmon fly imitation, I recently read that it was initially tied to represent the October caddis.
I don't have a recipe. They were (originally) made from wood (balsa usually) in two
slices, that got lashed onto the hook, over and under horse hair wings.
And then painted, using one or more stencils, in order to make their characteristic
segmenting details. The inventor was Norman Means of Missoula Montana,
whose local nickname (I'm pretty sure) was Paul Bunyan.
A friend gave me an old fly box that their great uncle once owned. The uncle lived in Missoula and one of the compartments had ten of these. What a find. I was told by someone who would know that they are the real deal. However, they were most likely made in the fifties. The distinctive markings are from a sticker, not painted.
The Bunyan Bug, a unique floating salmonfly, or October Caddis, imitation resurfaced in the film "A River Runs Throut It', from the Norman McClean book of the same name. It is the fly that Brad Pitt borrowed from his brother to catch the giant trout from the Blackfoot River. It was a famous fly in Montanain the 1940s and 50s, usually displayed on a card of about 2-dozen flies. Jimmy LeMert at Patrick's Fly Shop had several on display and may still have.