I don't really know anything about East West, except they hailed from SF. Most of their jackets that I see for sale are tan-coloured and are very expensive. Style Eyes did a jacket, in deer skin I think, that certainly looked very similar to an East West one, though I'm not sure if it was an actual repro.
Just a blind guess. I know that some of the Stones (along with most successful rock stars of the 60's/70's) were regular East West wearers. They made jackets in all colors (they literally made rainbow colored jackets even). They used deer, goat, steer, buffalo, horse, etc. Some of their designs were way over the top, some fairly traditional (half-belt style, etc), but they were always superbly executed and made from top quality leather. I have a seal brown horsehide western shirt-style East West jacket that is just awesome. Gets more comments from chicks than other other jacket I own. Even Grant had to admit it was cool.