How can you I find out what variation my Ethan Allen revolver is?

Perhaps a good place to start would be to find a copy of Flayderman's Guide to Antique American Firearms- you may be able to request a copy through your local library. This is a fairly comprehensive book with good descriptions and illustrations of thousands of antique firearms. You might also check for gun dealers in your area that know antique firearms, or check out a local gun show, where dealers in antique firearms have been neatly gathered in one spot for your convenience.