I just had a discussion with a Canadian bowyer who does a lot of snake skin overlays and he says it is a very simple process. He uses a high quality wood glue and trims the skins to shape after they are glued. The scales then need to be shaved off and the job is done.
I just bought a 1961 KS for 66 bucks and I am going to do it with skins. I seem to be on a snake theme these days (just bought an ACS with Western Diamondback overlays, a Pit Viper compound and a Mamba compound in the last few weeks).
Come up and join us for the North American Long Bow Safari next summer which will be held just outside of Calgary. He will be there with lots of Western Diamondback and Prairie Rattler skins for sale. PM me and I can get you more details.
DDave